whats_new.txt

.. currentmodule:: sklearn


===============
Release history
===============

.. _changes_0_18_2:

Version 0.18.2
==============

**June 20, 2017**

.. topic:: Last release with Python 2.6 support

    Scikit-learn 0.18 is the last major release of scikit-learn to support Python 2.6.
    Later versions of scikit-learn will require Python 2.7 or above.


Changelog
---------
    - Fixes for compatibility with NumPy 1.13.0: :issue:`7946` :issue:`8355` by `Loic Esteve`_.

    - Minor compatibility changes in the examples :issue:`9010` :issue:`8040` :issue:`9149`.


Code Contributors
-----------------
Aman Dalmia, Loic Esteve, Nate Guerin, Sergei Lebedev


.. _changes_0_18_1:

Version 0.18.1
==============

**November 11, 2016**

.. topic:: Last release with Python 2.6 support

    Scikit-learn 0.18 is the last major release of scikit-learn to support Python 2.6.
    Later versions of scikit-learn will require Python 2.7 or above.


Changelog
---------

Enhancements
.........
   - Improved ``sample_without_replacement`` speed by utilizing
     numpy.random.permutation for most cases. As a result,
     samples may differ in this release for a fixed random state.
     Affected estimators:
      - :class:`ensemble.BaggingClassifier`
      - :class:`ensemble.BaggingRegressor`
      - :class:`linear_model.RANSACRegressor`
      - :class:`model_selection.RandomizedSearchCV`
      - :class:`random_projection.SparseRandomProjection`
     This also affects the :meth:`datasets.make_classification`
     method.

Bug fixes
.........

   - Fix issue where ``min_grad_norm`` and ``n_iter_without_progress``
     parameters were not being utilised by :class:`manifold.TSNE`.
     :issue:`6497` by :user:`Sebastian Säger <ssaeger>`

   - Fix bug for svm's decision values when ``decision_function_shape``
     is ``ovr`` in :class:`svm.SVC`.
     :class:`svm.SVC`'s decision_function was incorrect from versions
     0.17.0 through 0.18.0.
     :issue:`7724` by `Bing Tian Dai`_

   - Attribute ``explained_variance_ratio`` of
     :class:`discriminant_analysis.LinearDiscriminantAnalysis` calculated
     with SVD and Eigen solver are now of the same length. :issue:`7632`
     by :user:`JPFrancoia <JPFrancoia>`

   - Fixes issue in :ref:`univariate_feature_selection` where score 
     functions were not accepting multi-label targets. :issue:`7676`
     by `Mohammed Affan`_

   - Fixed setting parameters when calling ``fit`` multiple times on
     :class:`feature_selection.SelectFromModel`. :issue:`7756` by `Andreas Müller`_

   - Fixes issue in ``partial_fit`` method of
     :class:`multiclass.OneVsRestClassifier` when number of classes used in
     ``partial_fit`` was less than the total number of classes in the
     data. :issue:`7786` by `Srivatsan Ramesh`_

   - Fixes issue in :class:`calibration.CalibratedClassifierCV` where
     the sum of probabilities of each class for a data was not 1, and
     ``CalibratedClassifierCV`` now handles the case where the training set
     has less number of classes than the total data. :issue:`7799` by
     `Srivatsan Ramesh`_

   - Fix a bug where :class:`sklearn.feature_selection.SelectFdr` did not
     exactly implement Benjamini-Hochberg procedure. It formerly may have
     selected fewer features than it should.
     :issue:`7490` by :user:`Peng Meng <mpjlu>`.

   - :class:`sklearn.manifold.LocallyLinearEmbedding` now correctly handles
     integer inputs. :issue:`6282` by `Jake Vanderplas`_.

   - The ``min_weight_fraction_leaf`` parameter of tree-based classifiers and
     regressors now assumes uniform sample weights by default if the
     ``sample_weight`` argument is not passed to the ``fit`` function.
     Previously, the parameter was silently ignored. :issue:`7301`
     by :user:`Nelson Liu <nelson-liu>`.

   - Numerical issue with :class:`linear_model.RidgeCV` on centered data when
     `n_features > n_samples`. :issue:`6178` by `Bertrand Thirion`_

   - Tree splitting criterion classes' cloning/pickling is now memory safe
     :issue:`7680` by :user:`Ibraim Ganiev <olologin>`.

   - Fixed a bug where :class:`decomposition.NMF` sets its ``n_iters_``
     attribute in `transform()`. :issue:`7553` by :user:`Ekaterina
     Krivich <kiote>`.

   - :class:`sklearn.linear_model.LogisticRegressionCV` now correctly handles
     string labels. :issue:`5874` by `Raghav RV`_.

   - Fixed a bug where :func:`sklearn.model_selection.train_test_split` raised
     an error when ``stratify`` is a list of string labels. :issue:`7593` by
     `Raghav RV`_.

   - Fixed a bug where :class:`sklearn.model_selection.GridSearchCV` and
     :class:`sklearn.model_selection.RandomizedSearchCV` were not pickleable
     because of a pickling bug in ``np.ma.MaskedArray``. :issue:`7594` by
     `Raghav RV`_.

   - All cross-validation utilities in :mod:`sklearn.model_selection` now
     permit one time cross-validation splitters for the ``cv`` parameter. Also
     non-deterministic cross-validation splitters (where multiple calls to
     ``split`` produce dissimilar splits) can be used as ``cv`` parameter.
     The :class:`sklearn.model_selection.GridSearchCV` will cross-validate each
     parameter setting on the split produced by the first ``split`` call
     to the cross-validation splitter.  :issue:`7660` by `Raghav RV`_.

API changes summary
-------------------

Trees and forests

   - The ``min_weight_fraction_leaf`` parameter of tree-based classifiers and
     regressors now assumes uniform sample weights by default if the
     ``sample_weight`` argument is not passed to the ``fit`` function.
     Previously, the parameter was silently ignored. (`#7301
     <https://github.com/scikit-learn/scikit-learn/pull/7301>`_) by `Nelson
     Liu`_.

   - Tree splitting criterion classes' cloning/pickling is now memory safe
     (`#7680 <https://github.com/scikit-learn/scikit-learn/pull/7680>`_).
     By `Ibraim Ganiev`_.


Linear, kernelized and related models

   - Length of `explained_variance_ratio` of
     :class:`discriminant_analysis.LinearDiscriminantAnalysis`
     changed for both Eigen and SVD solvers. The attribute has now a length
     of min(n_components, n_classes - 1). :issue:`7632`
     by :user:`JPFrancoia <JPFrancoia>`

   - Numerical issue with :class:`linear_model.RidgeCV` on centered data when
     `n_features > n_samples`. (`#6178
     <https://github.com/scikit-learn/scikit-learn/pull/6178>`_) by `Bertrand
     Thirion`_


Code Contributors
-----------------
Aashi, affanv14, Alexander Junge, Alexandre Gramfort, Aman Dalmia, Andreas
Mueller, Andrew Jackson, Andrew Smith, Angus Williams, Artem Golubin, Arthur
Douillard, Artsiom, Bertrand Thirion, Bing Tian Dai, Brian Burns, CJ Carey,
Charlton Austin, chkoar, Dave Elliott, David Kirkby, Deborah Gertrude Digges,
ditenberg, E. Lynch-Klarup, Ekaterina Krivich, Fabian Egli, ferria, fukatani,
Gael Varoquaux, Giorgio Patrini, Grzegorz Szpak, He Chen, guoci, Ibraim Ganiev,
Iván Vallés, JPFrancoia, Jake VanderPlas, Joel Nothman, Jon Crall, Jonathan
Rahn, Jonathan Striebel, Josh Karnofsky, Julien Aubert, Kathy Chen, Kaushik
Lakshmikanth, Kevin Yap, Kyle Gilliam, ljwolf, Loic Esteve, Mainak Jas,
Maniteja Nandana, Mathieu Blondel, Mehul Ahuja, Michele Lacchia, Mikhail
Korobov, Nelle Varoquaux, Nelson Liu, Nicole Vavrova, nuffe, Olivier Grisel, Om
Prakash, Patrick Carlson, Pieter Arthur de Jong, polmauri, Rafael Possas,
Raghav R V, Ruifeng Zheng, Sam Shleifer, Sebastian Saeger, Sourav Singh,
Srivatsan, Thierry Guillemot, toastedcornflakes, Tom Dupré la Tour,
vibrantabhi19, waterponey


.. _changes_0_18:

Version 0.18
============

**September 28, 2016**

.. topic:: Last release with Python 2.6 support

    Scikit-learn 0.18 will be the last version of scikit-learn to support Python 2.6.
    Later versions of scikit-learn will require Python 2.7 or above.

.. _model_selection_changes:

Model Selection Enhancements and API Changes
--------------------------------------------

  - **The model_selection module**

    The new module :mod:`sklearn.model_selection`, which groups together the
    functionalities of formerly :mod:`sklearn.cross_validation`,
    :mod:`sklearn.grid_search` and :mod:`sklearn.learning_curve`, introduces new
    possibilities such as nested cross-validation and better manipulation of
    parameter searches with Pandas.

    Many things will stay the same but there are some key differences. Read
    below to know more about the changes.

  - **Data-independent CV splitters enabling nested cross-validation**

    The new cross-validation splitters, defined in the
    :mod:`sklearn.model_selection`, are no longer initialized with any
    data-dependent parameters such as ``y``. Instead they expose a
    :func:`split` method that takes in the data and yields a generator for the
    different splits.

    This change makes it possible to use the cross-validation splitters to
    perform nested cross-validation, facilitated by
    :class:`model_selection.GridSearchCV` and
    :class:`model_selection.RandomizedSearchCV` utilities.

  - **The enhanced cv_results_ attribute**

    The new ``cv_results_`` attribute (of :class:`model_selection.GridSearchCV`
    and :class:`model_selection.RandomizedSearchCV`) introduced in lieu of the
    ``grid_scores_`` attribute is a dict of 1D arrays with elements in each
    array corresponding to the parameter settings (i.e. search candidates).

    The ``cv_results_`` dict can be easily imported into ``pandas`` as a
    ``DataFrame`` for exploring the search results.

    The ``cv_results_`` arrays include scores for each cross-validation split
    (with keys such as ``'split0_test_score'``), as well as their mean
    (``'mean_test_score'``) and standard deviation (``'std_test_score'``).

    The ranks for the search candidates (based on their mean
    cross-validation score) is available at ``cv_results_['rank_test_score']``.

    The parameter values for each parameter is stored separately as numpy
    masked object arrays. The value, for that search candidate, is masked if
    the corresponding parameter is not applicable. Additionally a list of all
    the parameter dicts are stored at ``cv_results_['params']``.

  - **Parameters n_folds and n_iter renamed to n_splits**

    Some parameter names have changed:
    The ``n_folds`` parameter in new :class:`model_selection.KFold`,
    :class:`model_selection.GroupKFold` (see below for the name change),
    and :class:`model_selection.StratifiedKFold` is now renamed to
    ``n_splits``. The ``n_iter`` parameter in
    :class:`model_selection.ShuffleSplit`, the new class
    :class:`model_selection.GroupShuffleSplit` and
    :class:`model_selection.StratifiedShuffleSplit` is now renamed to
    ``n_splits``.

  - **Rename of splitter classes which accepts group labels along with data**

    The cross-validation splitters ``LabelKFold``,
    ``LabelShuffleSplit``, ``LeaveOneLabelOut`` and ``LeavePLabelOut`` have
    been renamed to :class:`model_selection.GroupKFold`,
    :class:`model_selection.GroupShuffleSplit`,
    :class:`model_selection.LeaveOneGroupOut` and
    :class:`model_selection.LeavePGroupsOut` respectively.

    Note the change from singular to plural form in
    :class:`model_selection.LeavePGroupsOut`.

  - **Fit parameter labels renamed to groups**

    The ``labels`` parameter in the :func:`split` method of the newly renamed
    splitters :class:`model_selection.GroupKFold`,
    :class:`model_selection.LeaveOneGroupOut`,
    :class:`model_selection.LeavePGroupsOut`,
    :class:`model_selection.GroupShuffleSplit` is renamed to ``groups``
    following the new nomenclature of their class names.

  - **Parameter n_labels renamed to n_groups**

    The parameter ``n_labels`` in the newly renamed
    :class:`model_selection.LeavePGroupsOut` is changed to ``n_groups``.

  - Training scores and Timing information

    ``cv_results_`` also includes the training scores for each
    cross-validation split (with keys such as ``'split0_train_score'``), as
    well as their mean (``'mean_train_score'``) and standard deviation
    (``'std_train_score'``). To avoid the cost of evaluating training score,
    set ``return_train_score=False``.

    Additionally the mean and standard deviation of the times taken to split,
    train and score the model across all the cross-validation splits is
    available at the key ``'mean_time'`` and ``'std_time'`` respectively.

Changelog
---------

New features
............

Classifiers and Regressors

   - The Gaussian Process module has been reimplemented and now offers classification
     and regression estimators through :class:`gaussian_process.GaussianProcessClassifier`
     and  :class:`gaussian_process.GaussianProcessRegressor`. Among other things, the new
     implementation supports kernel engineering, gradient-based hyperparameter optimization or
     sampling of functions from GP prior and GP posterior. Extensive documentation and
     examples are provided. By `Jan Hendrik Metzen`_.

   - Added new supervised learning algorithm: :ref:`Multi-layer Perceptron <multilayer_perceptron>`
     :issue:`3204` by :user:`Issam H. Laradji <IssamLaradji>`

   - Added :class:`linear_model.HuberRegressor`, a linear model robust to outliers.
     :issue:`5291` by `Manoj Kumar`_.

   - Added the :class:`multioutput.MultiOutputRegressor` meta-estimator. It
     converts single output regressors to multi-ouput regressors by fitting
     one regressor per output. By :user:`Tim Head <betatim>`.

Other estimators

   - New :class:`mixture.GaussianMixture` and :class:`mixture.BayesianGaussianMixture`
     replace former mixture models, employing faster inference
     for sounder results. :issue:`7295` by :user:`Wei Xue <xuewei4d>` and 
     :user:`Thierry Guillemot <tguillemot>`.

   - Class :class:`decomposition.RandomizedPCA` is now factored into :class:`decomposition.PCA`
     and it is available calling with parameter ``svd_solver='randomized'``.
     The default number of ``n_iter`` for ``'randomized'`` has changed to 4. The old
     behavior of PCA is recovered by ``svd_solver='full'``. An additional solver
     calls ``arpack`` and performs truncated (non-randomized) SVD. By default,
     the best solver is selected depending on the size of the input and the
     number of components requested. :issue:`5299` by :user:`Giorgio Patrini <giorgiop>`.

   - Added two functions for mutual information estimation:
     :func:`feature_selection.mutual_info_classif` and
     :func:`feature_selection.mutual_info_regression`. These functions can be
     used in :class:`feature_selection.SelectKBest` and
     :class:`feature_selection.SelectPercentile` as score functions.
     By :user:`Andrea Bravi <AndreaBravi>` and :user:`Nikolay Mayorov <nmayorov>`.

   - Added the :class:`ensemble.IsolationForest` class for anomaly detection based on
     random forests. By `Nicolas Goix`_.

   - Added ``algorithm="elkan"`` to :class:`cluster.KMeans` implementing
     Elkan's fast K-Means algorithm. By `Andreas Müller`_.

Model selection and evaluation

   - Added :func:`metrics.cluster.fowlkes_mallows_score`, the Fowlkes Mallows
     Index which measures the similarity of two clusterings of a set of points
     By :user:`Arnaud Fouchet <afouchet>` and :user:`Thierry Guillemot <tguillemot>`.

   - Added :func:`metrics.calinski_harabaz_score`, which computes the Calinski
     and Harabaz score to evaluate the resulting clustering of a set of points.
     By :user:`Arnaud Fouchet <afouchet>` and :user:`Thierry Guillemot <tguillemot>`.

   - Added new cross-validation splitter
     :class:`model_selection.TimeSeriesSplit` to handle time series data.
     :issue:`6586` by :user:`YenChen Lin <yenchenlin>`

   - The cross-validation iterators are replaced by cross-validation splitters
     available from :mod:`sklearn.model_selection`, allowing for nested
     cross-validation. See :ref:`model_selection_changes` for more information.
     :issue:`4294` by `Raghav RV`_.

Enhancements
............

Trees and ensembles

   - Added a new splitting criterion for :class:`tree.DecisionTreeRegressor`,
     the mean absolute error. This criterion can also be used in
     :class:`ensemble.ExtraTreesRegressor`,
     :class:`ensemble.RandomForestRegressor`, and the gradient boosting
     estimators. :issue:`6667` by :user:`Nelson Liu <nelson-liu>`.

   - Added weighted impurity-based early stopping criterion for decision tree
     growth. :issue:`6954` by :user:`Nelson Liu <nelson-liu>`

   - The random forest, extra tree and decision tree estimators now has a
     method ``decision_path`` which returns the decision path of samples in
     the tree. By `Arnaud Joly`_.

   - A new example has been added unveiling the decision tree structure.
     By `Arnaud Joly`_.

   - Random forest, extra trees, decision trees and gradient boosting estimator
     accept the parameter ``min_samples_split`` and ``min_samples_leaf``
     provided as a percentage of the training samples. By :user:`yelite <yelite>` and `Arnaud Joly`_.

   - Gradient boosting estimators accept the parameter ``criterion`` to specify
     to splitting criterion used in built decision trees.
     :issue:`6667` by :user:`Nelson Liu <nelson-liu>`.

   - The memory footprint is reduced (sometimes greatly) for
     :class:`ensemble.bagging.BaseBagging` and classes that inherit from it,
     i.e, :class:`ensemble.BaggingClassifier`,
     :class:`ensemble.BaggingRegressor`, and :class:`ensemble.IsolationForest`,
     by dynamically generating attribute ``estimators_samples_`` only when it is
     needed. By :user:`David Staub <staubda>`.

   - Added ``n_jobs`` and ``sample_weight`` parameters for
     :class:`ensemble.VotingClassifier` to fit underlying estimators in parallel.
     :issue:`5805` by :user:`Ibraim Ganiev <olologin>`.

Linear, kernelized and related models

   - In :class:`linear_model.LogisticRegression`, the SAG solver is now
     available in the multinomial case. :issue:`5251` by `Tom Dupre la Tour`_.

   - :class:`linear_model.RANSACRegressor`, :class:`svm.LinearSVC` and
     :class:`svm.LinearSVR` now support ``sample_weight``.
     By :user:`Imaculate <Imaculate>`.

   - Add parameter ``loss`` to :class:`linear_model.RANSACRegressor` to measure the
     error on the samples for every trial. By `Manoj Kumar`_.

   - Prediction of out-of-sample events with Isotonic Regression
     (:class:`isotonic.IsotonicRegression`) is now much faster (over 1000x in tests with synthetic
     data). By :user:`Jonathan Arfa <jarfa>`.

   - Isotonic regression (:class:`isotonic.IsotonicRegression`) now uses a better algorithm to avoid
     `O(n^2)` behavior in pathological cases, and is also generally faster
     (:issue:`#6691`). By `Antony Lee`_.

   - :class:`naive_bayes.GaussianNB` now accepts data-independent class-priors
     through the parameter ``priors``. By :user:`Guillaume Lemaitre <glemaitre>`.

   - :class:`linear_model.ElasticNet` and :class:`linear_model.Lasso`
     now works with ``np.float32`` input data without converting it
     into ``np.float64``. This allows to reduce the memory
     consumption. :issue:`6913` by :user:`YenChen Lin <yenchenlin>`.

   - :class:`semi_supervised.LabelPropagation` and :class:`semi_supervised.LabelSpreading`
     now accept arbitrary kernel functions in addition to strings ``knn`` and ``rbf``.
     :issue:`5762` by :user:`Utkarsh Upadhyay <musically-ut>`.

Decomposition, manifold learning and clustering

   - Added ``inverse_transform`` function to :class:`decomposition.NMF` to compute
     data matrix of original shape. By :user:`Anish Shah <AnishShah>`.

   - :class:`cluster.KMeans` and :class:`cluster.MiniBatchKMeans` now works
     with ``np.float32`` and ``np.float64`` input data without converting it.
     This allows to reduce the memory consumption by using ``np.float32``.
     :issue:`6846` by :user:`Sebastian Säger <ssaeger>` and 
     :user:`YenChen Lin <yenchenlin>`.

Preprocessing and feature selection

   - :class:`preprocessing.RobustScaler` now accepts ``quantile_range`` parameter.
     :issue:`5929` by :user:`Konstantin Podshumok <podshumok>`.

   - :class:`feature_extraction.FeatureHasher` now accepts string values.
     :issue:`6173` by :user:`Ryad Zenine <ryadzenine>` and 
     :user:`Devashish Deshpande <dsquareindia>`.

   - Keyword arguments can now be supplied to ``func`` in
     :class:`preprocessing.FunctionTransformer` by means of the ``kw_args``
     parameter. By `Brian McFee`_.

   - :class:`feature_selection.SelectKBest` and :class:`feature_selection.SelectPercentile`
     now accept score functions that take X, y as input and return only the scores.
     By :user:`Nikolay Mayorov <nmayorov>`.

Model evaluation and meta-estimators

   - :class:`multiclass.OneVsOneClassifier` and :class:`multiclass.OneVsRestClassifier`
     now support ``partial_fit``. By :user:`Asish Panda <kaichogami>` and 
     :user:`Philipp Dowling <phdowling>`.

   - Added support for substituting or disabling :class:`pipeline.Pipeline`
     and :class:`pipeline.FeatureUnion` components using the ``set_params``
     interface that powers :mod:`sklearn.grid_search`.
     See :ref:`sphx_glr_plot_compare_reduction.py`. By `Joel Nothman`_ and
     :user:`Robert McGibbon <rmcgibbo>`.

   - The new ``cv_results_`` attribute of :class:`model_selection.GridSearchCV`
     (and :class:`model_selection.RandomizedSearchCV`) can be easily imported
     into pandas as a ``DataFrame``. Ref :ref:`model_selection_changes` for
     more information. :issue:`6697` by `Raghav RV`_.

   - Generalization of :func:`model_selection.cross_val_predict`.
     One can pass method names such as `predict_proba` to be used in the cross
     validation framework instead of the default `predict`.
     By :user:`Ori Ziv <zivori>` and :user:`Sears Merritt <merritts>`.

   - The training scores and time taken for training followed by scoring for
     each search candidate are now available at the ``cv_results_`` dict.
     See :ref:`model_selection_changes` for more information.
     :issue:`7325` by :user:`Eugene Chen <eyc88>` and `Raghav RV`_.

Metrics

   - Added ``labels`` flag to :class:`metrics.log_loss` to to explicitly provide
     the labels when the number of classes in ``y_true`` and ``y_pred`` differ.
     :issue:`7239` by :user:`Hong Guangguo <hongguangguo>` with help from 
     :user:`Mads Jensen <indianajensen>` and :user:`Nelson Liu <nelson-liu>`.

   - Support sparse contingency matrices in cluster evaluation
     (:mod:`metrics.cluster.supervised`) to scale to a large number of
     clusters.
     :issue:`7419` by :user:`Gregory Stupp <stuppie>` and `Joel Nothman`_.

   - Add ``sample_weight`` parameter to :func:`metrics.matthews_corrcoef`.
     By :user:`Jatin Shah <jatinshah>` and `Raghav RV`_.

   - Speed up :func:`metrics.silhouette_score` by using vectorized operations.
     By `Manoj Kumar`_.

   - Add ``sample_weight`` parameter to :func:`metrics.confusion_matrix`.
     By :user:`Bernardo Stein <DanielSidhion>`.

Miscellaneous

   - Added ``n_jobs`` parameter to :class:`feature_selection.RFECV` to compute
     the score on the test folds in parallel. By `Manoj Kumar`_

   - Codebase does not contain C/C++ cython generated files: they are
     generated during build. Distribution packages will still contain generated
     C/C++ files. By :user:`Arthur Mensch <arthurmensch>`.

   - Reduce the memory usage for 32-bit float input arrays of
     :func:`utils.sparse_func.mean_variance_axis` and
     :func:`utils.sparse_func.incr_mean_variance_axis` by supporting cython
     fused types. By :user:`YenChen Lin <yenchenlin>`.

   - The :func:`ignore_warnings` now accept a category argument to ignore only
     the warnings of a specified type. By :user:`Thierry Guillemot <tguillemot>`.

   - Added parameter ``return_X_y`` and return type ``(data, target) : tuple`` option to
     :func:`load_iris` dataset
     :issue:`7049`,
     :func:`load_breast_cancer` dataset
     :issue:`7152`,
     :func:`load_digits` dataset,
     :func:`load_diabetes` dataset,
     :func:`load_linnerud` dataset,
     :func:`load_boston` dataset
     :issue:`7154` by
     :user:`Manvendra Singh<manu-chroma>`.

   - Simplification of the ``clone`` function, deprecate support for estimators
     that modify parameters in ``__init__``. :issue:`5540` by `Andreas Müller`_.

   - When unpickling a scikit-learn estimator in a different version than the one
     the estimator was trained with, a ``UserWarning`` is raised, see :ref:`the documentation
     on model persistence <persistence_limitations>` for more details. (:issue:`7248`)
     By `Andreas Müller`_.

Bug fixes
.........

Trees and ensembles

    - Random forest, extra trees, decision trees and gradient boosting
      won't accept anymore ``min_samples_split=1`` as at least 2 samples
      are required to split a decision tree node. By `Arnaud Joly`_

    - :class:`ensemble.VotingClassifier` now raises ``NotFittedError`` if ``predict``,
      ``transform`` or ``predict_proba`` are called on the non-fitted estimator.
      by `Sebastian Raschka`_.

    - Fix bug where :class:`ensemble.AdaBoostClassifier` and
      :class:`ensemble.AdaBoostRegressor` would perform poorly if the
      ``random_state`` was fixed
      (:issue:`7411`). By `Joel Nothman`_.

    - Fix bug in ensembles with randomization where the ensemble would not
      set ``random_state`` on base estimators in a pipeline or similar nesting.
      (:issue:`7411`). Note, results for :class:`ensemble.BaggingClassifier`
      :class:`ensemble.BaggingRegressor`, :class:`ensemble.AdaBoostClassifier`
      and :class:`ensemble.AdaBoostRegressor` will now differ from previous
      versions. By `Joel Nothman`_.

Linear, kernelized and related models

    - Fixed incorrect gradient computation for ``loss='squared_epsilon_insensitive'`` in
      :class:`linear_model.SGDClassifier` and :class:`linear_model.SGDRegressor`
      (:issue:`6764`). By :user:`Wenhua Yang <geekoala>`.

    - Fix bug in :class:`linear_model.LogisticRegressionCV` where
      ``solver='liblinear'`` did not accept ``class_weights='balanced``.
      (:issue:`6817`). By `Tom Dupre la Tour`_.

    - Fix bug in :class:`neighbors.RadiusNeighborsClassifier` where an error
      occurred when there were outliers being labelled and a weight function
      specified (:issue:`6902`).  By
      `LeonieBorne <https://github.com/LeonieBorne>`_.

    - Fix :class:`linear_model.ElasticNet` sparse decision function to match
      output with dense in the multioutput case.

Decomposition, manifold learning and clustering

    - :class:`decomposition.RandomizedPCA` default number of `iterated_power` is 4 instead of 3.
      :issue:`5141` by :user:`Giorgio Patrini <giorgiop>`.

    - :func:`utils.extmath.randomized_svd` performs 4 power iterations by default, instead or 0.
      In practice this is enough for obtaining a good approximation of the
      true eigenvalues/vectors in the presence of noise. When `n_components` is
      small (``< .1 * min(X.shape)``) `n_iter` is set to 7, unless the user specifies
      a higher number. This improves precision with few components.
      :issue:`5299` by :user:`Giorgio Patrini<giorgiop>`.

    - Whiten/non-whiten inconsistency between components of :class:`decomposition.PCA`
      and :class:`decomposition.RandomizedPCA` (now factored into PCA, see the
      New features) is fixed. `components_` are stored with no whitening.
      :issue:`5299` by :user:`Giorgio Patrini <giorgiop>`.

    - Fixed bug in :func:`manifold.spectral_embedding` where diagonal of unnormalized
      Laplacian matrix was incorrectly set to 1. :issue:`4995` by :user:`Peter Fischer <yanlend>`.

    - Fixed incorrect initialization of :func:`utils.arpack.eigsh` on all
      occurrences. Affects :class:`cluster.bicluster.SpectralBiclustering`,
      :class:`decomposition.KernelPCA`, :class:`manifold.LocallyLinearEmbedding`,
      and :class:`manifold.SpectralEmbedding` (:issue:`5012`). By 
      :user:`Peter Fischer <yanlend>`.

    - Attribute ``explained_variance_ratio_`` calculated with the SVD solver
      of :class:`discriminant_analysis.LinearDiscriminantAnalysis` now returns
      correct results. By :user:`JPFrancoia <JPFrancoia>`

Preprocessing and feature selection

    - :func:`preprocessing.data._transform_selected` now always passes a copy
      of ``X`` to transform function when ``copy=True`` (:issue:`7194`). By `Caio
      Oliveira <https://github.com/caioaao>`_.

Model evaluation and meta-estimators

    - :class:`model_selection.StratifiedKFold` now raises error if all n_labels
      for individual classes is less than n_folds.
      :issue:`6182` by :user:`Devashish Deshpande <dsquareindia>`.

    - Fixed bug in :class:`model_selection.StratifiedShuffleSplit`
      where train and test sample could overlap in some edge cases,
      see :issue:`6121` for
      more details. By `Loic Esteve`_.

    - Fix in :class:`sklearn.model_selection.StratifiedShuffleSplit` to
      return splits of size ``train_size`` and ``test_size`` in all cases
      (:issue:`6472`). By `Andreas Müller`_.

    - Cross-validation of :class:`OneVsOneClassifier` and
      :class:`OneVsRestClassifier` now works with precomputed kernels.
      :issue:`7350` by :user:`Russell Smith <rsmith54>`.

    - Fix incomplete ``predict_proba`` method delegation from
      :class:`model_selection.GridSearchCV` to
      :class:`linear_model.SGDClassifier` (:issue:`7159`)
      by `Yichuan Liu <https://github.com/yl565>`_.

Metrics

    - Fix bug in :func:`metrics.silhouette_score` in which clusters of
      size 1 were incorrectly scored. They should get a score of 0.
      By `Joel Nothman`_.

    - Fix bug in :func:`metrics.silhouette_samples` so that it now works with
      arbitrary labels, not just those ranging from 0 to n_clusters - 1.

    - Fix bug where expected and adjusted mutual information were incorrect if
      cluster contingency cells exceeded ``2**16``. By `Joel Nothman`_.

    - :func:`metrics.pairwise.pairwise_distances` now converts arrays to
      boolean arrays when required in ``scipy.spatial.distance``.
      :issue:`5460` by `Tom Dupre la Tour`_.

    - Fix sparse input support in :func:`metrics.silhouette_score` as well as
      example examples/text/document_clustering.py. By :user:`YenChen Lin <yenchenlin>`.

    - :func:`metrics.roc_curve` and :func:`metrics.precision_recall_curve` no
      longer round ``y_score`` values when creating ROC curves; this was causing
      problems for users with very small differences in scores (:issue:`7353`).

Miscellaneous

    - :func:`model_selection.tests._search._check_param_grid` now works correctly with all types
      that extends/implements `Sequence` (except string), including range (Python 3.x) and xrange
      (Python 2.x). :issue:`7323` by Viacheslav Kovalevskyi.

    - :func:`utils.extmath.randomized_range_finder` is more numerically stable when many
      power iterations are requested, since it applies LU normalization by default.
      If ``n_iter<2`` numerical issues are unlikely, thus no normalization is applied.
      Other normalization options are available: ``'none', 'LU'`` and ``'QR'``.
      :issue:`5141` by :user:`Giorgio Patrini <giorgiop>`.

    - Fix a bug where some formats of ``scipy.sparse`` matrix, and estimators
      with them as parameters, could not be passed to :func:`base.clone`.
      By `Loic Esteve`_.

    - :func:`datasets.load_svmlight_file` now is able to read long int QID values.
      :issue:`7101` by :user:`Ibraim Ganiev <olologin>`.


API changes summary
-------------------

Linear, kernelized and related models

   - ``residual_metric`` has been deprecated in :class:`linear_model.RANSACRegressor`.
     Use ``loss`` instead. By `Manoj Kumar`_.

   - Access to public attributes ``.X_`` and ``.y_`` has been deprecated in
     :class:`isotonic.IsotonicRegression`. By :user:`Jonathan Arfa <jarfa>`.

Decomposition, manifold learning and clustering

   - The old :class:`mixture.DPGMM` is deprecated in favor of the new
     :class:`mixture.BayesianGaussianMixture` (with the parameter
     ``weight_concentration_prior_type='dirichlet_process'``).
     The new class solves the computational
     problems of the old class and computes the Gaussian mixture with a
     Dirichlet process prior faster than before.
     :issue:`7295` by :user:`Wei Xue <xuewei4d>` and :user:`Thierry Guillemot <tguillemot>`.

   - The old :class:`mixture.VBGMM` is deprecated in favor of the new
     :class:`mixture.BayesianGaussianMixture` (with the parameter
     ``weight_concentration_prior_type='dirichlet_distribution'``).
     The new class solves the computational
     problems of the old class and computes the Variational Bayesian Gaussian
     mixture faster than before.
     :issue:`6651` by :user:`Wei Xue <xuewei4d>` and :user:`Thierry Guillemot <tguillemot>`.

   - The old :class:`mixture.GMM` is deprecated in favor of the new
     :class:`mixture.GaussianMixture`. The new class computes the Gaussian mixture
     faster than before and some of computational problems have been solved.
     :issue:`6666` by :user:`Wei Xue <xuewei4d>` and :user:`Thierry Guillemot <tguillemot>`.

Model evaluation and meta-estimators

   - The :mod:`sklearn.cross_validation`, :mod:`sklearn.grid_search` and
     :mod:`sklearn.learning_curve` have been deprecated and the classes and
     functions have been reorganized into the :mod:`sklearn.model_selection`
     module. Ref :ref:`model_selection_changes` for more information.
     :issue:`4294` by `Raghav RV`_.

   - The ``grid_scores_`` attribute of :class:`model_selection.GridSearchCV`
     and :class:`model_selection.RandomizedSearchCV` is deprecated in favor of
     the attribute ``cv_results_``.
     Ref :ref:`model_selection_changes` for more information.
     :issue:`6697` by `Raghav RV`_.

   - The parameters ``n_iter`` or ``n_folds`` in old CV splitters are replaced
     by the new parameter ``n_splits`` since it can provide a consistent
     and unambiguous interface to represent the number of train-test splits.
     :issue:`7187` by :user:`YenChen Lin <yenchenlin>`.

   - ``classes`` parameter was renamed to ``labels`` in
     :func:`metrics.hamming_loss`. :issue:`7260` by :user:`Sebastián Vanrell <srvanrell>`.

   - The splitter classes ``LabelKFold``, ``LabelShuffleSplit``,
     ``LeaveOneLabelOut`` and ``LeavePLabelsOut`` are renamed to
     :class:`model_selection.GroupKFold`,
     :class:`model_selection.GroupShuffleSplit`,
     :class:`model_selection.LeaveOneGroupOut`
     and :class:`model_selection.LeavePGroupsOut` respectively.
     Also the parameter ``labels`` in the :func:`split` method of the newly
     renamed splitters :class:`model_selection.LeaveOneGroupOut` and
     :class:`model_selection.LeavePGroupsOut` is renamed to
     ``groups``. Additionally in :class:`model_selection.LeavePGroupsOut`,
     the parameter ``n_labels`` is renamed to ``n_groups``.
     :issue:`6660` by `Raghav RV`_.

Code Contributors
-----------------
Aditya Joshi, Alejandro, Alexander Fabisch, Alexander Loginov, Alexander
Minyushkin, Alexander Rudy, Alexandre Abadie, Alexandre Abraham, Alexandre
Gramfort, Alexandre Saint, alexfields, Alvaro Ulloa, alyssaq, Amlan Kar,
Andreas Mueller, andrew giessel, Andrew Jackson, Andrew McCulloh, Andrew
Murray, Anish Shah, Arafat, Archit Sharma, Ariel Rokem, Arnaud Joly, Arnaud
Rachez, Arthur Mensch, Ash Hoover, asnt, b0noI, Behzad Tabibian, Bernardo,
Bernhard Kratzwald, Bhargav Mangipudi, blakeflei, Boyuan Deng, Brandon Carter,
Brett Naul, Brian McFee, Caio Oliveira, Camilo Lamus, Carol Willing, Cass,
CeShine Lee, Charles Truong, Chyi-Kwei Yau, CJ Carey, codevig, Colin Ni, Dan
Shiebler, Daniel, Daniel Hnyk, David Ellis, David Nicholson, David Staub, David
Thaler, David Warshaw, Davide Lasagna, Deborah, definitelyuncertain, Didi
Bar-Zev, djipey, dsquareindia, edwinENSAE, Elias Kuthe, Elvis DOHMATOB, Ethan
White, Fabian Pedregosa, Fabio Ticconi, fisache, Florian Wilhelm, Francis,
Francis O'Donovan, Gael Varoquaux, Ganiev Ibraim, ghg, Gilles Louppe, Giorgio
Patrini, Giovanni Cherubin, Giovanni Lanzani, Glenn Qian, Gordon
Mohr, govin-vatsan, Graham Clenaghan, Greg Reda, Greg Stupp, Guillaume
Lemaitre, Gustav Mörtberg, halwai, Harizo Rajaona, Harry Mavroforakis,
hashcode55, hdmetor, Henry Lin, Hobson Lane, Hugo Bowne-Anderson,
Igor Andriushchenko, Imaculate, Inki Hwang, Isaac Sijaranamual,
Ishank Gulati, Issam Laradji, Iver Jordal, jackmartin, Jacob Schreiber, Jake
Vanderplas, James Fiedler, James Routley, Jan Zikes, Janna Brettingen, jarfa, Jason
Laska, jblackburne, jeff levesque, Jeffrey Blackburne, Jeffrey04, Jeremy Hintz,
jeremynixon, Jeroen, Jessica Yung, Jill-Jênn Vie, Jimmy Jia, Jiyuan Qian, Joel
Nothman, johannah, John, John Boersma, John Kirkham, John Moeller,
jonathan.striebel, joncrall, Jordi, Joseph Munoz, Joshua Cook, JPFrancoia,
jrfiedler, JulianKahnert, juliathebrave, kaichogami, KamalakerDadi, Kenneth
Lyons, Kevin Wang, kingjr, kjell, Konstantin Podshumok, Kornel Kielczewski,
Krishna Kalyan, krishnakalyan3, Kvle Putnam, Kyle Jackson, Lars Buitinck,
ldavid, LeiG, LeightonZhang, Leland McInnes, Liang-Chi Hsieh, Lilian Besson,
lizsz, Loic Esteve, Louis Tiao, Léonie Borne, Mads Jensen, Maniteja Nandana,
Manoj Kumar, Manvendra Singh, Marco, Mario Krell, Mark Bao, Mark Szepieniec,
Martin Madsen, MartinBpr, MaryanMorel, Massil, Matheus, Mathieu Blondel,
Mathieu Dubois, Matteo, Matthias Ekman, Max Moroz, Michael Scherer, michiaki
ariga, Mikhail Korobov, Moussa Taifi, mrandrewandrade, Mridul Seth, nadya-p,
Naoya Kanai, Nate George, Nelle Varoquaux, Nelson Liu, Nick James,
NickleDave, Nico, Nicolas Goix, Nikolay Mayorov, ningchi, nlathia,
okbalefthanded, Okhlopkov, Olivier Grisel, Panos Louridas, Paul Strickland,
Perrine Letellier, pestrickland, Peter Fischer, Pieter, Ping-Yao, Chang,
practicalswift, Preston Parry, Qimu Zheng, Rachit Kansal, Raghav RV,
Ralf Gommers, Ramana.S, Rammig, Randy Olson, Rob Alexander, Robert Lutz,
Robin Schucker, Rohan Jain, Ruifeng Zheng, Ryan Yu, Rémy Léone, saihttam,
Saiwing Yeung, Sam Shleifer, Samuel St-Jean, Sartaj Singh, Sasank Chilamkurthy,
saurabh.bansod, Scott Andrews, Scott Lowe, seales, Sebastian Raschka, Sebastian
Saeger, Sebastián Vanrell, Sergei Lebedev, shagun Sodhani, shanmuga cv,
Shashank Shekhar, shawpan, shengxiduan, Shota, shuckle16, Skipper Seabold,
sklearn-ci, SmedbergM, srvanrell, Sébastien Lerique, Taranjeet, themrmax,
Thierry, Thierry Guillemot, Thomas, Thomas Hallock, Thomas Moreau, Tim Head,
tKammy, toastedcornflakes, Tom, TomDLT, Toshihiro Kamishima, tracer0tong, Trent
Hauck, trevorstephens, Tue Vo, Varun, Varun Jewalikar, Viacheslav, Vighnesh
Birodkar, Vikram, Villu Ruusmann, Vinayak Mehta, walter, waterponey, Wenhua
Yang, Wenjian Huang, Will Welch, wyseguy7, xyguo, yanlend, Yaroslav Halchenko,
yelite, Yen, YenChenLin, Yichuan Liu, Yoav Ram, Yoshiki, Zheng RuiFeng, zivori, Óscar Nájera


.. currentmodule:: sklearn

.. _changes_0_17_1:

Version 0.17.1
==============

**February 18, 2016**

Changelog
---------

Bug fixes
.........


    - Upgrade vendored joblib to version 0.9.4 that fixes an important bug in
      ``joblib.Parallel`` that can silently yield to wrong results when working
      on datasets larger than 1MB:
      https://github.com/joblib/joblib/blob/0.9.4/CHANGES.rst

    - Fixed reading of Bunch pickles generated with scikit-learn
      version <= 0.16. This can affect users who have already
      downloaded a dataset with scikit-learn 0.16 and are loading it
      with scikit-learn 0.17. See :issue:`6196` for
      how this affected :func:`datasets.fetch_20newsgroups`. By `Loic
      Esteve`_.

    - Fixed a bug that prevented using ROC AUC score to perform grid search on
      several CPU / cores on large arrays. See :issue:`6147`
      By `Olivier Grisel`_.

    - Fixed a bug that prevented to properly set the ``presort`` parameter
      in :class:`ensemble.GradientBoostingRegressor`. See :issue:`5857`
      By Andrew McCulloh.

    - Fixed a joblib error when evaluating the perplexity of a
      :class:`decomposition.LatentDirichletAllocation` model. See :issue:`6258`
      By Chyi-Kwei Yau.

.. _changes_0_17:

Version 0.17
============

**November 5, 2015**

Changelog
---------

New features
............

   - All the Scaler classes but :class:`preprocessing.RobustScaler` can be fitted online by
     calling `partial_fit`. By :user:`Giorgio Patrini <giorgiop>`.

   - The new class :class:`ensemble.VotingClassifier` implements a
     "majority rule" / "soft voting" ensemble classifier to combine
     estimators for classification. By `Sebastian Raschka`_.

   - The new class :class:`preprocessing.RobustScaler` provides an
     alternative to :class:`preprocessing.StandardScaler` for feature-wise
     centering and range normalization that is robust to outliers.
     By :user:`Thomas Unterthiner <untom>`.

   - The new class :class:`preprocessing.MaxAbsScaler` provides an
     alternative to :class:`preprocessing.MinMaxScaler` for feature-wise
     range normalization when the data is already centered or sparse.
     By :user:`Thomas Unterthiner <untom>`.

   - The new class :class:`preprocessing.FunctionTransformer` turns a Python
     function into a ``Pipeline``-compatible transformer object.
     By Joe Jevnik.

   - The new classes :class:`cross_validation.LabelKFold` and
     :class:`cross_validation.LabelShuffleSplit` generate train-test folds,
     respectively similar to :class:`cross_validation.KFold` and
     :class:`cross_validation.ShuffleSplit`, except that the folds are
     conditioned on a label array. By `Brian McFee`_, :user:`Jean 
     Kossaifi <JeanKossaifi>` and `Gilles Louppe`_.

   - :class:`decomposition.LatentDirichletAllocation` implements the Latent
     Dirichlet Allocation topic model with online  variational
     inference. By :user:`Chyi-Kwei Yau <chyikwei>`, with code based on an implementation
     by Matt Hoffman. (:issue:`3659`)

   - The new solver ``sag`` implements a Stochastic Average Gradient descent
     and is available in both :class:`linear_model.LogisticRegression` and
     :class:`linear_model.Ridge`. This solver is very efficient for large
     datasets. By :user:`Danny Sullivan <dsullivan7>` and `Tom Dupre la Tour`_.
     (:issue:`4738`)

   - The new solver ``cd`` implements a Coordinate Descent in
     :class:`decomposition.NMF`. Previous solver based on Projected Gradient is
     still available setting new parameter ``solver`` to ``pg``, but is
     deprecated and will be removed in 0.19, along with
     :class:`decomposition.ProjectedGradientNMF` and parameters ``sparseness``,
     ``eta``, ``beta`` and ``nls_max_iter``. New parameters ``alpha`` and
     ``l1_ratio`` control L1 and L2 regularization, and ``shuffle`` adds a
     shuffling step in the ``cd`` solver.
     By `Tom Dupre la Tour`_ and `Mathieu Blondel`_.

Enhancements
............
   - :class:`manifold.TSNE` now supports approximate optimization via the
     Barnes-Hut method, leading to much faster fitting. By Christopher Erick Moody.
     (:issue:`4025`)

   - :class:`cluster.mean_shift_.MeanShift` now supports parallel execution,
     as implemented in the ``mean_shift`` function. By :user:`Martino
     Sorbaro <martinosorb>`.

   - :class:`naive_bayes.GaussianNB` now supports fitting with ``sample_weight``.
     By `Jan Hendrik Metzen`_.

   - :class:`dummy.DummyClassifier` now supports a prior fitting strategy.
     By `Arnaud Joly`_.

   - Added a ``fit_predict`` method for :class:`mixture.GMM` and subclasses.
     By :user:`Cory Lorenz <clorenz7>`.

   - Added the :func:`metrics.label_ranking_loss` metric.
     By `Arnaud Joly`_.

   - Added the :func:`metrics.cohen_kappa_score` metric.

   - Added a ``warm_start`` constructor parameter to the bagging ensemble
     models to increase the size of the ensemble. By :user:`Tim Head <betatim>`.

   - Added option to use multi-output regression metrics without averaging.
     By Konstantin Shmelkov and :user:`Michael Eickenberg<eickenberg>`.

   - Added ``stratify`` option to :func:`cross_validation.train_test_split`
     for stratified splitting. By Miroslav Batchkarov.

   - The :func:`tree.export_graphviz` function now supports aesthetic
     improvements for :class:`tree.DecisionTreeClassifier` and
     :class:`tree.DecisionTreeRegressor`, including options for coloring nodes
     by their majority class or impurity, showing variable names, and using
     node proportions instead of raw sample counts. By `Trevor Stephens`_.

   - Improved speed of ``newton-cg`` solver in
     :class:`linear_model.LogisticRegression`, by avoiding loss computation.
     By `Mathieu Blondel`_ and `Tom Dupre la Tour`_.

   - The ``class_weight="auto"`` heuristic in classifiers supporting
     ``class_weight`` was deprecated and replaced by the ``class_weight="balanced"``
     option, which has a simpler formula and interpretation.
     By `Hanna Wallach`_ and `Andreas Müller`_.

   - Add ``class_weight`` parameter to automatically weight samples by class
     frequency for :class:`linear_model.PassiveAgressiveClassifier`. By
     `Trevor Stephens`_.

   - Added backlinks from the API reference pages to the user guide. By
     `Andreas Müller`_.

   - The ``labels`` parameter to :func:`sklearn.metrics.f1_score`,
     :func:`sklearn.metrics.fbeta_score`,
     :func:`sklearn.metrics.recall_score` and
     :func:`sklearn.metrics.precision_score` has been extended.
     It is now possible to ignore one or more labels, such as where
     a multiclass problem has a majority class to ignore. By `Joel Nothman`_.

   - Add ``sample_weight`` support to :class:`linear_model.RidgeClassifier`.
     By `Trevor Stephens`_.

   - Provide an option for sparse output from
     :func:`sklearn.metrics.pairwise.cosine_similarity`. By 
     :user:`Jaidev Deshpande <jaidevd>`.

   - Add :func:`minmax_scale` to provide a function interface for
     :class:`MinMaxScaler`. By :user:`Thomas Unterthiner <untom>`.

   - ``dump_svmlight_file`` now handles multi-label datasets.
     By Chih-Wei Chang.

   - RCV1 dataset loader (:func:`sklearn.datasets.fetch_rcv1`).
     By `Tom Dupre la Tour`_.

   - The "Wisconsin Breast Cancer" classical two-class classification dataset
     is now included in scikit-learn, available with
     :func:`sklearn.dataset.load_breast_cancer`.

   - Upgraded to joblib 0.9.3 to benefit from the new automatic batching of
     short tasks. This makes it possible for scikit-learn to benefit from
     parallelism when many very short tasks are executed in parallel, for
     instance by the :class:`grid_search.GridSearchCV` meta-estimator
     with ``n_jobs > 1`` used with a large grid of parameters on a small
     dataset. By `Vlad Niculae`_, `Olivier Grisel`_ and `Loic Esteve`_.

   - For more details about changes in joblib 0.9.3 see the release notes:
     https://github.com/joblib/joblib/blob/master/CHANGES.rst#release-093

   - Improved speed (3 times per iteration) of
     :class:`decomposition.DictLearning` with coordinate descent method
     from :class:`linear_model.Lasso`. By :user:`Arthur Mensch <arthurmensch>`.

   - Parallel processing (threaded) for queries of nearest neighbors
     (using the ball-tree) by Nikolay Mayorov.

   - Allow :func:`datasets.make_multilabel_classification` to output
     a sparse ``y``. By Kashif Rasul.

   - :class:`cluster.DBSCAN` now accepts a sparse matrix of precomputed
     distances, allowing memory-efficient distance precomputation. By
     `Joel Nothman`_.

   - :class:`tree.DecisionTreeClassifier` now exposes an ``apply`` method
     for retrieving the leaf indices samples are predicted as. By
     :user:`Daniel Galvez <galv>` and `Gilles Louppe`_.

   - Speed up decision tree regressors, random forest regressors, extra trees
     regressors and gradient boosting estimators by computing a proxy
     of the impurity improvement during the tree growth. The proxy quantity is
     such that the split that maximizes this value also maximizes the impurity
     improvement. By `Arnaud Joly`_, :user:`Jacob Schreiber <jmschrei>`
     and `Gilles Louppe`_.

   - Speed up tree based methods by reducing the number of computations needed
     when computing the impurity measure taking into account linear
     relationship of the computed statistics. The effect is particularly
     visible with extra trees and on datasets with categorical or sparse
     features. By `Arnaud Joly`_.

   - :class:`ensemble.GradientBoostingRegressor` and
     :class:`ensemble.GradientBoostingClassifier` now expose an ``apply``
     method for retrieving the leaf indices each sample ends up in under
     each try. By :user:`Jacob Schreiber <jmschrei>`.

   - Add ``sample_weight`` support to :class:`linear_model.LinearRegression`.
     By Sonny Hu. (:issue:`#4881`)

   - Add ``n_iter_without_progress`` to :class:`manifold.TSNE` to control
     the stopping criterion. By Santi Villalba. (:issue:`5186`)

   - Added optional parameter ``random_state`` in :class:`linear_model.Ridge`
     , to set the seed of the pseudo random generator used in ``sag`` solver. By `Tom Dupre la Tour`_.

   - Added optional parameter ``warm_start`` in
     :class:`linear_model.LogisticRegression`. If set to True, the solvers
     ``lbfgs``, ``newton-cg`` and ``sag`` will be initialized with the
     coefficients computed in the previous fit. By `Tom Dupre la Tour`_.

   - Added ``sample_weight`` support to :class:`linear_model.LogisticRegression` for
     the ``lbfgs``, ``newton-cg``, and ``sag`` solvers. By `Valentin Stolbunov`_.
     Support added to the ``liblinear`` solver. By `Manoj Kumar`_.

   - Added optional parameter ``presort`` to :class:`ensemble.GradientBoostingRegressor`
     and :class:`ensemble.GradientBoostingClassifier`, keeping default behavior
     the same. This allows gradient boosters to turn off presorting when building
     deep trees or using sparse data. By :user:`Jacob Schreiber <jmschrei>`.

   - Altered :func:`metrics.roc_curve` to drop unnecessary thresholds by
     default. By :user:`Graham Clenaghan <gclenaghan>`.

   - Added :class:`feature_selection.SelectFromModel` meta-transformer which can
     be used along with estimators that have `coef_` or `feature_importances_`
     attribute to select important features of the input data. By
     :user:`Maheshakya Wijewardena <maheshakya>`, `Joel Nothman`_ and `Manoj Kumar`_.

   - Added :func:`metrics.pairwise.laplacian_kernel`.  By `Clyde Fare <https://github.com/Clyde-fare>`_.

   - :class:`covariance.GraphLasso` allows separate control of the convergence criterion
     for the Elastic-Net subproblem via  the ``enet_tol`` parameter.

   - Improved verbosity in :class:`decomposition.DictionaryLearning`.

   - :class:`ensemble.RandomForestClassifier` and
     :class:`ensemble.RandomForestRegressor` no longer explicitly store the
     samples used in bagging, resulting in a much reduced memory footprint for
     storing random forest models.

   - Added ``positive`` option to :class:`linear_model.Lars` and
     :func:`linear_model.lars_path` to force coefficients to be positive.
     (:issue:`5131`)

   - Added the ``X_norm_squared`` parameter to :func:`metrics.pairwise.euclidean_distances`
     to provide precomputed squared norms for ``X``.

   - Added the ``fit_predict`` method to :class:`pipeline.Pipeline`.

   - Added the :func:`preprocessing.min_max_scale` function.

Bug fixes
.........

    - Fixed non-determinism in :class:`dummy.DummyClassifier` with sparse
      multi-label output. By `Andreas Müller`_.

    - Fixed the output shape of :class:`linear_model.RANSACRegressor` to
      ``(n_samples, )``. By `Andreas Müller`_.

    - Fixed bug in :class:`decomposition.DictLearning` when ``n_jobs < 0``. By
      `Andreas Müller`_.

    - Fixed bug where :class:`grid_search.RandomizedSearchCV` could consume a
      lot of memory for large discrete grids. By `Joel Nothman`_.

    - Fixed bug in :class:`linear_model.LogisticRegressionCV` where `penalty` was ignored
      in the final fit. By `Manoj Kumar`_.

    - Fixed bug in :class:`ensemble.forest.ForestClassifier` while computing
      oob_score and X is a sparse.csc_matrix. By :user:`Ankur Ankan <ankurankan>`.

    - All regressors now consistently handle and warn when given ``y`` that is of
      shape ``(n_samples, 1)``. By `Andreas Müller`_ and Henry Lin.
      (:issue:`5431`)

    - Fix in :class:`cluster.KMeans` cluster reassignment for sparse input by
      `Lars Buitinck`_.

    - Fixed a bug in :class:`lda.LDA` that could cause asymmetric covariance
      matrices when using shrinkage. By `Martin Billinger`_.

    - Fixed :func:`cross_validation.cross_val_predict` for estimators with
      sparse predictions. By Buddha Prakash.

    - Fixed the ``predict_proba`` method of :class:`linear_model.LogisticRegression`
      to use soft-max instead of one-vs-rest normalization. By `Manoj Kumar`_.
      (:issue:`5182`)

    - Fixed the :func:`partial_fit` method of :class:`linear_model.SGDClassifier`
      when called with ``average=True``. By :user:`Andrew Lamb <andylamb>`.
      (:issue:`5282`)

    - Dataset fetchers use different filenames under Python 2 and Python 3 to
      avoid pickling compatibility issues. By `Olivier Grisel`_.
      (:issue:`5355`)

    - Fixed a bug in :class:`naive_bayes.GaussianNB` which caused classification
      results to depend on scale. By `Jake Vanderplas`_.

    - Fixed temporarily :class:`linear_model.Ridge`, which was incorrect
      when fitting the intercept in the case of sparse data. The fix
      automatically changes the solver to 'sag' in this case.
      :issue:`5360` by `Tom Dupre la Tour`_.

    - Fixed a performance bug in :class:`decomposition.RandomizedPCA` on data
      with a large number of features and fewer samples. (:issue:`4478`)
      By `Andreas Müller`_, `Loic Esteve`_ and :user:`Giorgio Patrini <giorgiop>`.

    - Fixed bug in :class:`cross_decomposition.PLS` that yielded unstable and
      platform dependent output, and failed on `fit_transform`.
      By :user:`Arthur Mensch <arthurmensch>`.

    - Fixes to the ``Bunch`` class used to store datasets.

    - Fixed :func:`ensemble.plot_partial_dependence` ignoring the
      ``percentiles`` parameter.

    - Providing a ``set`` as vocabulary in ``CountVectorizer`` no longer
      leads to inconsistent results when pickling.

    - Fixed the conditions on when a precomputed Gram matrix needs to
      be recomputed in :class:`linear_model.LinearRegression`,
      :class:`linear_model.OrthogonalMatchingPursuit`,
      :class:`linear_model.Lasso` and :class:`linear_model.ElasticNet`.

    - Fixed inconsistent memory layout in the coordinate descent solver
      that affected :class:`linear_model.DictionaryLearning` and
      :class:`covariance.GraphLasso`. (:issue:`5337`)
      By `Olivier Grisel`_.

    - :class:`manifold.LocallyLinearEmbedding` no longer ignores the ``reg``
      parameter.

    - Nearest Neighbor estimators with custom distance metrics can now be pickled.
      (:issue:`4362`)

    - Fixed a bug in :class:`pipeline.FeatureUnion` where ``transformer_weights``
      were not properly handled when performing grid-searches.

    - Fixed a bug in :class:`linear_model.LogisticRegression` and
      :class:`linear_model.LogisticRegressionCV` when using
      ``class_weight='balanced'```or ``class_weight='auto'``.
      By `Tom Dupre la Tour`_.

    - Fixed bug :issue:`5495` when
      doing OVR(SVC(decision_function_shape="ovr")). Fixed by 
      :user:`Elvis Dohmatob <dohmatob>`.


API changes summary
-------------------
    - Attribute `data_min`, `data_max` and `data_range` in
      :class:`preprocessing.MinMaxScaler` are deprecated and won't be available
      from 0.19. Instead, the class now exposes `data_min_`, `data_max_`
      and `data_range_`. By :user:`Giorgio Patrini <giorgiop>`.

    - All Scaler classes now have an `scale_` attribute, the feature-wise
      rescaling applied by their `transform` methods. The old attribute `std_`
      in :class:`preprocessing.StandardScaler` is deprecated and superseded
      by `scale_`; it won't be available in 0.19. By :user:`Giorgio Patrini <giorgiop>`.

    - :class:`svm.SVC`` and :class:`svm.NuSVC` now have an ``decision_function_shape``
      parameter to make their decision function of shape ``(n_samples, n_classes)``
      by setting ``decision_function_shape='ovr'``. This will be the default behavior
      starting in 0.19. By `Andreas Müller`_.

    - Passing 1D data arrays as input to estimators is now deprecated as it
      caused confusion in how the array elements should be interpreted
      as features or as samples. All data arrays are now expected
      to be explicitly shaped ``(n_samples, n_features)``.
      By :user:`Vighnesh Birodkar <vighneshbirodkar>`.

    - :class:`lda.LDA` and :class:`qda.QDA` have been moved to
      :class:`discriminant_analysis.LinearDiscriminantAnalysis` and
      :class:`discriminant_analysis.QuadraticDiscriminantAnalysis`.

    - The ``store_covariance`` and ``tol`` parameters have been moved from
      the fit method to the constructor in
      :class:`discriminant_analysis.LinearDiscriminantAnalysis` and the
      ``store_covariances`` and ``tol`` parameters have been moved from the
      fit method to the constructor in
      :class:`discriminant_analysis.QuadraticDiscriminantAnalysis`.

    - Models inheriting from ``_LearntSelectorMixin`` will no longer support the
      transform methods. (i.e,  RandomForests, GradientBoosting, LogisticRegression,
      DecisionTrees, SVMs and SGD related models). Wrap these models around the
      metatransfomer :class:`feature_selection.SelectFromModel` to remove
      features (according to `coefs_` or `feature_importances_`)
      which are below a certain threshold value instead.

    - :class:`cluster.KMeans` re-runs cluster-assignments in case of non-convergence,
      to ensure consistency of ``predict(X)`` and ``labels_``. By
      :user:`Vighnesh Birodkar <vighneshbirodkar>`.

    - Classifier and Regressor models are now tagged as such using the
      ``_estimator_type`` attribute.

    - Cross-validation iterators always provide indices into training and test set,
      not boolean masks.

    - The ``decision_function`` on all regressors was deprecated and will be
      removed in 0.19.  Use ``predict`` instead.

    - :func:`datasets.load_lfw_pairs` is deprecated and will be removed in 0.19.
      Use :func:`datasets.fetch_lfw_pairs` instead.

    - The deprecated ``hmm`` module was removed.

    - The deprecated ``Bootstrap`` cross-validation iterator was removed.

    - The deprecated ``Ward`` and ``WardAgglomerative`` classes have been removed.
      Use :class:`clustering.AgglomerativeClustering` instead.

    - :func:`cross_validation.check_cv` is now a public function.

    - The property ``residues_`` of :class:`linear_model.LinearRegression` is deprecated
      and will be removed in 0.19.

    - The deprecated ``n_jobs`` parameter of :class:`linear_model.LinearRegression` has been moved
      to the constructor.

    - Removed deprecated ``class_weight`` parameter from :class:`linear_model.SGDClassifier`'s ``fit``
      method. Use the construction parameter instead.

    - The deprecated support for the sequence of sequences (or list of lists) multilabel
      format was removed. To convert to and from the supported binary
      indicator matrix format, use
      :class:`MultiLabelBinarizer <preprocessing.MultiLabelBinarizer>`.

    - The behavior of calling the ``inverse_transform`` method of ``Pipeline.pipeline`` will
      change in 0.19. It will no longer reshape one-dimensional input to two-dimensional input.

    - The deprecated attributes ``indicator_matrix_``, ``multilabel_`` and ``classes_`` of
      :class:`preprocessing.LabelBinarizer` were removed.

    - Using ``gamma=0`` in :class:`svm.SVC` and :class:`svm.SVR` to automatically set the
      gamma to ``1. / n_features`` is deprecated and will be removed in 0.19.
      Use ``gamma="auto"`` instead.

Code Contributors
-----------------
Aaron Schumacher, Adithya Ganesh, akitty, Alexandre Gramfort, Alexey Grigorev,
Ali Baharev, Allen Riddell, Ando Saabas, Andreas Mueller, Andrew Lamb, Anish
Shah, Ankur Ankan, Anthony Erlinger, Ari Rouvinen, Arnaud Joly, Arnaud Rachez,
Arthur Mensch, banilo, Barmaley.exe, benjaminirving, Boyuan Deng, Brett Naul,
Brian McFee, Buddha Prakash, Chi Zhang, Chih-Wei Chang, Christof Angermueller,
Christoph Gohlke, Christophe Bourguignat, Christopher Erick Moody, Chyi-Kwei
Yau, Cindy Sridharan, CJ Carey, Clyde-fare, Cory Lorenz, Dan Blanchard, Daniel
Galvez, Daniel Kronovet, Danny Sullivan, Data1010, David, David D Lowe, David
Dotson, djipey, Dmitry Spikhalskiy, Donne Martin, Dougal J. Sutherland, Dougal
Sutherland, edson duarte, Eduardo Caro, Eric Larson, Eric Martin, Erich
Schubert, Fernando Carrillo, Frank C. Eckert, Frank Zalkow, Gael Varoquaux,
Ganiev Ibraim, Gilles Louppe, Giorgio Patrini, giorgiop, Graham Clenaghan,
Gryllos Prokopis, gwulfs, Henry Lin, Hsuan-Tien Lin, Immanuel Bayer, Ishank
Gulati, Jack Martin, Jacob Schreiber, Jaidev Deshpande, Jake Vanderplas, Jan
Hendrik Metzen, Jean Kossaifi, Jeffrey04, Jeremy, jfraj, Jiali Mei,
Joe Jevnik, Joel Nothman, John Kirkham, John Wittenauer, Joseph, Joshua Loyal,
Jungkook Park, KamalakerDadi, Kashif Rasul, Keith Goodman, Kian Ho, Konstantin
Shmelkov, Kyler Brown, Lars Buitinck, Lilian Besson, Loic Esteve, Louis Tiao,
maheshakya, Maheshakya Wijewardena, Manoj Kumar, MarkTab marktab.net, Martin
Ku, Martin Spacek, MartinBpr, martinosorb, MaryanMorel, Masafumi Oyamada,
Mathieu Blondel, Matt Krump, Matti Lyra, Maxim Kolganov, mbillinger, mhg,
Michael Heilman, Michael Patterson, Miroslav Batchkarov, Nelle Varoquaux,
Nicolas, Nikolay Mayorov, Olivier Grisel, Omer Katz, Óscar Nájera, Pauli
Virtanen, Peter Fischer, Peter Prettenhofer, Phil Roth, pianomania, Preston
Parry, Raghav RV, Rob Zinkov, Robert Layton, Rohan Ramanath, Saket Choudhary,
Sam Zhang, santi, saurabh.bansod, scls19fr, Sebastian Raschka, Sebastian
Saeger, Shivan Sornarajah, SimonPL, sinhrks, Skipper Seabold, Sonny Hu, sseg,
Stephen Hoover, Steven De Gryze, Steven Seguin, Theodore Vasiloudis, Thomas
Unterthiner, Tiago Freitas Pereira, Tian Wang, Tim Head, Timothy Hopper,
tokoroten, Tom Dupré la Tour, Trevor Stephens, Valentin Stolbunov, Vighnesh
Birodkar, Vinayak Mehta, Vincent, Vincent Michel, vstolbunov, wangz10, Wei Xue,
Yucheng Low, Yury Zhauniarovich, Zac Stewart, zhai_pro, Zichen Wang

.. _changes_0_1_16:

Version 0.16.1
===============

**April 14, 2015**

Changelog
---------

Bug fixes
.........

   - Allow input data larger than ``block_size`` in
     :class:`covariance.LedoitWolf` by `Andreas Müller`_.

   - Fix a bug in :class:`isotonic.IsotonicRegression` deduplication that
     caused unstable result in :class:`calibration.CalibratedClassifierCV` by
     `Jan Hendrik Metzen`_.

   - Fix sorting of labels in func:`preprocessing.label_binarize` by Michael Heilman.

   - Fix several stability and convergence issues in
     :class:`cross_decomposition.CCA` and
     :class:`cross_decomposition.PLSCanonical` by `Andreas Müller`_

   - Fix a bug in :class:`cluster.KMeans` when ``precompute_distances=False``
     on fortran-ordered data.

   - Fix a speed regression in :class:`ensemble.RandomForestClassifier`'s ``predict``
     and ``predict_proba`` by `Andreas Müller`_.

   - Fix a regression where ``utils.shuffle`` converted lists and dataframes to arrays, by `Olivier Grisel`_

.. _changes_0_16:

Version 0.16
============

**March 26, 2015**

Highlights
-----------

   - Speed improvements (notably in :class:`cluster.DBSCAN`), reduced memory
     requirements, bug-fixes and better default settings.

   - Multinomial Logistic regression and a path algorithm in
     :class:`linear_model.LogisticRegressionCV`.

   - Out-of core learning of PCA via :class:`decomposition.IncrementalPCA`.

   - Probability callibration of classifiers using
     :class:`calibration.CalibratedClassifierCV`.

   - :class:`cluster.Birch` clustering method for large-scale datasets.

   - Scalable approximate nearest neighbors search with Locality-sensitive
     hashing forests in :class:`neighbors.LSHForest`.

   - Improved error messages and better validation when using malformed input data.

   - More robust integration with pandas dataframes.

Changelog
---------

New features
............

   - The new :class:`neighbors.LSHForest` implements locality-sensitive hashing
     for approximate nearest neighbors search. By :user:`Maheshakya Wijewardena<maheshakya>`.

   - Added :class:`svm.LinearSVR`. This class uses the liblinear implementation
     of Support Vector Regression which is much faster for large
     sample sizes than :class:`svm.SVR` with linear kernel. By
     `Fabian Pedregosa`_ and Qiang Luo.

   - Incremental fit for :class:`GaussianNB <naive_bayes.GaussianNB>`.

   - Added ``sample_weight`` support to :class:`dummy.DummyClassifier` and
     :class:`dummy.DummyRegressor`. By `Arnaud Joly`_.

   - Added the :func:`metrics.label_ranking_average_precision_score` metrics.
     By `Arnaud Joly`_.

   - Add the :func:`metrics.coverage_error` metrics. By `Arnaud Joly`_.

   - Added :class:`linear_model.LogisticRegressionCV`. By
     `Manoj Kumar`_, `Fabian Pedregosa`_, `Gael Varoquaux`_
     and `Alexandre Gramfort`_.

   - Added ``warm_start`` constructor parameter to make it possible for any
     trained forest model to grow additional trees incrementally. By
     :user:`Laurent Direr<ldirer>`.

   - Added ``sample_weight`` support to :class:`ensemble.GradientBoostingClassifier` and
     :class:`ensemble.GradientBoostingRegressor`. By `Peter Prettenhofer`_.

   - Added :class:`decomposition.IncrementalPCA`, an implementation of the PCA
     algorithm that supports out-of-core learning with a ``partial_fit``
     method. By `Kyle Kastner`_.

   - Averaged SGD for :class:`SGDClassifier <linear_model.SGDClassifier>`
     and :class:`SGDRegressor <linear_model.SGDRegressor>` By
     :user:`Danny Sullivan <dsullivan7>`.

   - Added :func:`cross_val_predict <cross_validation.cross_val_predict>`
     function which computes cross-validated estimates. By `Luis Pedro Coelho`_

   - Added :class:`linear_model.TheilSenRegressor`, a robust
     generalized-median-based estimator. By :user:`Florian Wilhelm <FlorianWilhelm>`.

   - Added :func:`metrics.median_absolute_error`, a robust metric.
     By `Gael Varoquaux`_ and :user:`Florian Wilhelm <FlorianWilhelm>`.

   - Add :class:`cluster.Birch`, an online clustering algorithm. By
     `Manoj Kumar`_, `Alexandre Gramfort`_ and `Joel Nothman`_.

   - Added shrinkage support to :class:`discriminant_analysis.LinearDiscriminantAnalysis`
     using two new solvers. By :user:`Clemens Brunner <cle1109>` and `Martin Billinger`_.

   - Added :class:`kernel_ridge.KernelRidge`, an implementation of
     kernelized ridge regression.
     By `Mathieu Blondel`_ and `Jan Hendrik Metzen`_.

   - All solvers in :class:`linear_model.Ridge` now support `sample_weight`.
     By `Mathieu Blondel`_.

   - Added :class:`cross_validation.PredefinedSplit` cross-validation
     for fixed user-provided cross-validation folds.
     By :user:`Thomas Unterthiner <untom>`.

   - Added :class:`calibration.CalibratedClassifierCV`, an approach for
     calibrating the predicted probabilities of a classifier.
     By `Alexandre Gramfort`_, `Jan Hendrik Metzen`_, `Mathieu Blondel`_
     and :user:`Balazs Kegl <kegl>`.


Enhancements
............

   - Add option ``return_distance`` in :func:`hierarchical.ward_tree`
     to return distances between nodes for both structured and unstructured
     versions of the algorithm. By `Matteo Visconti di Oleggio Castello`_.
     The same option was added in :func:`hierarchical.linkage_tree`.
     By `Manoj Kumar`_

   - Add support for sample weights in scorer objects.  Metrics with sample
     weight support will automatically benefit from it. By `Noel Dawe`_ and
     `Vlad Niculae`_.

   - Added ``newton-cg`` and `lbfgs` solver support in
     :class:`linear_model.LogisticRegression`. By `Manoj Kumar`_.

   - Add ``selection="random"`` parameter to implement stochastic coordinate
     descent for :class:`linear_model.Lasso`, :class:`linear_model.ElasticNet`
     and related. By `Manoj Kumar`_.

   - Add ``sample_weight`` parameter to
     :func:`metrics.jaccard_similarity_score` and :func:`metrics.log_loss`.
     By :user:`Jatin Shah <jatinshah>`.

   - Support sparse multilabel indicator representation in
     :class:`preprocessing.LabelBinarizer` and
     :class:`multiclass.OneVsRestClassifier` (by :user:`Hamzeh Alsalhi <hamsal>` with thanks
     to Rohit Sivaprasad), as well as evaluation metrics (by
     `Joel Nothman`_).

   - Add ``sample_weight`` parameter to `metrics.jaccard_similarity_score`.
     By `Jatin Shah`.

   - Add support for multiclass in `metrics.hinge_loss`. Added ``labels=None``
     as optional parameter. By `Saurabh Jha`.

   - Add ``sample_weight`` parameter to `metrics.hinge_loss`.
     By `Saurabh Jha`.

   - Add ``multi_class="multinomial"`` option in
     :class:`linear_model.LogisticRegression` to implement a Logistic
     Regression solver that minimizes the cross-entropy or multinomial loss
     instead of the default One-vs-Rest setting. Supports `lbfgs` and
     `newton-cg` solvers. By `Lars Buitinck`_ and `Manoj Kumar`_. Solver option
     `newton-cg` by Simon Wu.

   - ``DictVectorizer`` can now perform ``fit_transform`` on an iterable in a
     single pass, when giving the option ``sort=False``. By :user:`Dan
     Blanchard <dan-blanchard>`.

   - :class:`GridSearchCV` and :class:`RandomizedSearchCV` can now be
     configured to work with estimators that may fail and raise errors on
     individual folds. This option is controlled by the `error_score`
     parameter. This does not affect errors raised on re-fit. By
     :user:`Michal Romaniuk <romaniukm>`.

   - Add ``digits`` parameter to `metrics.classification_report` to allow
     report to show different precision of floating point numbers. By
     :user:`Ian Gilmore <agileminor>`.

   - Add a quantile prediction strategy to the :class:`dummy.DummyRegressor`.
     By :user:`Aaron Staple <staple>`.

   - Add ``handle_unknown`` option to :class:`preprocessing.OneHotEncoder` to
     handle unknown categorical features more gracefully during transform.
     By `Manoj Kumar`_.

   - Added support for sparse input data to decision trees and their ensembles.
     By `Fares Hedyati`_ and `Arnaud Joly`_.

   - Optimized :class:`cluster.AffinityPropagation` by reducing the number of
     memory allocations of large temporary data-structures. By `Antony Lee`_.

   - Parellization of the computation of feature importances in random forest.
     By `Olivier Grisel`_ and `Arnaud Joly`_.

   - Add ``n_iter_`` attribute to estimators that accept a ``max_iter`` attribute
     in their constructor. By `Manoj Kumar`_.

   - Added decision function for :class:`multiclass.OneVsOneClassifier`
     By `Raghav RV`_ and :user:`Kyle Beauchamp <kyleabeauchamp>`.

   - :func:`neighbors.kneighbors_graph` and :func:`radius_neighbors_graph`
     support non-Euclidean metrics. By `Manoj Kumar`_

   - Parameter ``connectivity`` in :class:`cluster.AgglomerativeClustering`
     and family now accept callables that return a connectivity matrix.
     By `Manoj Kumar`_.

   - Sparse support for :func:`paired_distances`. By `Joel Nothman`_.

   - :class:`cluster.DBSCAN` now supports sparse input and sample weights and
     has been optimized: the inner loop has been rewritten in Cython and
     radius neighbors queries are now computed in batch. By `Joel Nothman`_
     and `Lars Buitinck`_.

   - Add ``class_weight`` parameter to automatically weight samples by class
     frequency for :class:`ensemble.RandomForestClassifier`,
     :class:`tree.DecisionTreeClassifier`, :class:`ensemble.ExtraTreesClassifier`
     and :class:`tree.ExtraTreeClassifier`. By `Trevor Stephens`_.

   - :class:`grid_search.RandomizedSearchCV` now does sampling without
     replacement if all parameters are given as lists. By `Andreas Müller`_.

   - Parallelized calculation of :func:`pairwise_distances` is now supported
     for scipy metrics and custom callables. By `Joel Nothman`_.

   - Allow the fitting and scoring of all clustering algorithms in
     :class:`pipeline.Pipeline`. By `Andreas Müller`_.

   - More robust seeding and improved error messages in :class:`cluster.MeanShift`
     by `Andreas Müller`_.

   - Make the stopping criterion for :class:`mixture.GMM`,
     :class:`mixture.DPGMM` and :class:`mixture.VBGMM` less dependent on the
     number of samples by thresholding the average log-likelihood change
     instead of its sum over all samples. By `Hervé Bredin`_.

   - The outcome of :func:`manifold.spectral_embedding` was made deterministic
     by flipping the sign of eigenvectors. By :user:`Hasil Sharma <Hasil-Sharma>`.

   - Significant performance and memory usage improvements in
     :class:`preprocessing.PolynomialFeatures`. By `Eric Martin`_.

   - Numerical stability improvements for :class:`preprocessing.StandardScaler`
     and :func:`preprocessing.scale`. By `Nicolas Goix`_

   - :class:`svm.SVC` fitted on sparse input now implements ``decision_function``.
     By `Rob Zinkov`_ and `Andreas Müller`_.

   - :func:`cross_validation.train_test_split` now preserves the input type,
     instead of converting to numpy arrays.


Documentation improvements
..........................

   - Added example of using :class:`FeatureUnion` for heterogeneous input.
     By :user:`Matt Terry <mrterry>`

   - Documentation on scorers was improved, to highlight the handling of loss
     functions. By :user:`Matt Pico <MattpSoftware>`.

   - A discrepancy between liblinear output and scikit-learn's wrappers
     is now noted. By `Manoj Kumar`_.

   - Improved documentation generation: examples referring to a class or
     function are now shown in a gallery on the class/function's API reference
     page. By `Joel Nothman`_.

   - More explicit documentation of sample generators and of data
     transformation. By `Joel Nothman`_.

   - :class:`sklearn.neighbors.BallTree` and :class:`sklearn.neighbors.KDTree`
     used to point to empty pages stating that they are aliases of BinaryTree.
     This has been fixed to show the correct class docs. By `Manoj Kumar`_.

   - Added silhouette plots for analysis of KMeans clustering using
     :func:`metrics.silhouette_samples` and :func:`metrics.silhouette_score`.
     See :ref:`sphx_glr_auto_examples_cluster_plot_kmeans_silhouette_analysis.py`

Bug fixes
.........
    - Metaestimators now support ducktyping for the presence of ``decision_function``,
      ``predict_proba`` and other methods. This fixes behavior of
      :class:`grid_search.GridSearchCV`,
      :class:`grid_search.RandomizedSearchCV`, :class:`pipeline.Pipeline`,
      :class:`feature_selection.RFE`, :class:`feature_selection.RFECV` when nested.
      By `Joel Nothman`_

    - The ``scoring`` attribute of grid-search and cross-validation methods is no longer
      ignored when a :class:`grid_search.GridSearchCV` is given as a base estimator or
      the base estimator doesn't have predict.

    - The function :func:`hierarchical.ward_tree` now returns the children in
      the same order for both the structured and unstructured versions. By
      `Matteo Visconti di Oleggio Castello`_.

    - :class:`feature_selection.RFECV` now correctly handles cases when
      ``step`` is not equal to 1. By :user:`Nikolay Mayorov <nmayorov>`

    - The :class:`decomposition.PCA` now undoes whitening in its
      ``inverse_transform``. Also, its ``components_`` now always have unit
      length. By :user:`Michael Eickenberg <eickenberg>`.

    - Fix incomplete download of the dataset when
      :func:`datasets.download_20newsgroups` is called. By `Manoj Kumar`_.

    - Various fixes to the Gaussian processes subpackage by Vincent Dubourg
      and Jan Hendrik Metzen.

    - Calling ``partial_fit`` with ``class_weight=='auto'`` throws an
      appropriate error message and suggests a work around.
      By :user:`Danny Sullivan <dsullivan7>`.

    - :class:`RBFSampler <kernel_approximation.RBFSampler>` with ``gamma=g``
      formerly approximated :func:`rbf_kernel <metrics.pairwise.rbf_kernel>`
      with ``gamma=g/2.``; the definition of ``gamma`` is now consistent,
      which may substantially change your results if you use a fixed value.
      (If you cross-validated over ``gamma``, it probably doesn't matter
      too much.) By :user:`Dougal Sutherland <dougalsutherland>`.

    - Pipeline object delegate the ``classes_`` attribute to the underlying
      estimator. It allows, for instance, to make bagging of a pipeline object.
      By `Arnaud Joly`_

    - :class:`neighbors.NearestCentroid` now uses the median as the centroid
      when metric is set to ``manhattan``. It was using the mean before.
      By `Manoj Kumar`_

    - Fix numerical stability issues in :class:`linear_model.SGDClassifier`
      and :class:`linear_model.SGDRegressor` by clipping large gradients and
      ensuring that weight decay rescaling is always positive (for large
      l2 regularization and large learning rate values).
      By `Olivier Grisel`_

    - When `compute_full_tree` is set to "auto", the full tree is
      built when n_clusters is high and is early stopped when n_clusters is
      low, while the behavior should be vice-versa in
      :class:`cluster.AgglomerativeClustering` (and friends).
      This has been fixed By `Manoj Kumar`_

    - Fix lazy centering of data in :func:`linear_model.enet_path` and
      :func:`linear_model.lasso_path`. It was centered around one. It has
      been changed to be centered around the origin. By `Manoj Kumar`_

    - Fix handling of precomputed affinity matrices in
      :class:`cluster.AgglomerativeClustering` when using connectivity
      constraints. By :user:`Cathy Deng <cathydeng>`

    - Correct ``partial_fit`` handling of ``class_prior`` for
      :class:`sklearn.naive_bayes.MultinomialNB` and
      :class:`sklearn.naive_bayes.BernoulliNB`. By `Trevor Stephens`_.

    - Fixed a crash in :func:`metrics.precision_recall_fscore_support`
      when using unsorted ``labels`` in the multi-label setting.
      By `Andreas Müller`_.

    - Avoid skipping the first nearest neighbor in the methods ``radius_neighbors``,
      ``kneighbors``, ``kneighbors_graph`` and ``radius_neighbors_graph`` in
      :class:`sklearn.neighbors.NearestNeighbors` and family, when the query
      data is not the same as fit data. By `Manoj Kumar`_.

    - Fix log-density calculation in the :class:`mixture.GMM` with
      tied covariance. By `Will Dawson`_

    - Fixed a scaling error in :class:`feature_selection.SelectFdr`
      where a factor ``n_features`` was missing. By `Andrew Tulloch`_

    - Fix zero division in :class:`neighbors.KNeighborsRegressor` and related
      classes when using distance weighting and having identical data points.
      By `Garret-R <https://github.com/Garrett-R>`_.

    - Fixed round off errors with non positive-definite covariance matrices
      in GMM. By :user:`Alexis Mignon <AlexisMignon>`.

    - Fixed a error in the computation of conditional probabilities in
      :class:`naive_bayes.BernoulliNB`. By `Hanna Wallach`_.

    - Make the method ``radius_neighbors`` of
      :class:`neighbors.NearestNeighbors` return the samples lying on the
      boundary for ``algorithm='brute'``. By `Yan Yi`_.

    - Flip sign of ``dual_coef_`` of :class:`svm.SVC`
      to make it consistent with the documentation and
      ``decision_function``. By Artem Sobolev.

    - Fixed handling of ties in :class:`isotonic.IsotonicRegression`.
      We now use the weighted average of targets (secondary method). By
      `Andreas Müller`_ and `Michael Bommarito <http://bommaritollc.com/>`_.

API changes summary
-------------------

    - :class:`GridSearchCV <grid_search.GridSearchCV>` and
      :func:`cross_val_score <cross_validation.cross_val_score>` and other
      meta-estimators don't convert pandas DataFrames into arrays any more,
      allowing DataFrame specific operations in custom estimators.

    - :func:`multiclass.fit_ovr`, :func:`multiclass.predict_ovr`,
      :func:`predict_proba_ovr`,
      :func:`multiclass.fit_ovo`, :func:`multiclass.predict_ovo`,
      :func:`multiclass.fit_ecoc` and :func:`multiclass.predict_ecoc`
      are deprecated. Use the underlying estimators instead.

    - Nearest neighbors estimators used to take arbitrary keyword arguments
      and pass these to their distance metric. This will no longer be supported
      in scikit-learn 0.18; use the ``metric_params`` argument instead.

    - `n_jobs` parameter of the fit method shifted to the constructor of the
       LinearRegression class.

    - The ``predict_proba`` method of :class:`multiclass.OneVsRestClassifier`
      now returns two probabilities per sample in the multiclass case; this
      is consistent with other estimators and with the method's documentation,
      but previous versions accidentally returned only the positive
      probability. Fixed by Will Lamond and `Lars Buitinck`_.

    - Change default value of precompute in :class:`ElasticNet` and :class:`Lasso`
      to False. Setting precompute to "auto" was found to be slower when
      n_samples > n_features since the computation of the Gram matrix is
      computationally expensive and outweighs the benefit of fitting the Gram
      for just one alpha.
      ``precompute="auto"`` is now deprecated and will be removed in 0.18
      By `Manoj Kumar`_.

    - Expose ``positive`` option in :func:`linear_model.enet_path` and
      :func:`linear_model.enet_path` which constrains coefficients to be
      positive. By `Manoj Kumar`_.

    - Users should now supply an explicit ``average`` parameter to
      :func:`sklearn.metrics.f1_score`, :func:`sklearn.metrics.fbeta_score`,
      :func:`sklearn.metrics.recall_score` and
      :func:`sklearn.metrics.precision_score` when performing multiclass
      or multilabel (i.e. not binary) classification. By `Joel Nothman`_.

    - `scoring` parameter for cross validation now accepts `'f1_micro'`,
      `'f1_macro'` or `'f1_weighted'`. `'f1'` is now for binary classification
      only. Similar changes apply to `'precision'` and `'recall'`.
      By `Joel Nothman`_.

    - The ``fit_intercept``, ``normalize`` and ``return_models`` parameters in
      :func:`linear_model.enet_path` and :func:`linear_model.lasso_path` have
      been removed. They were deprecated since 0.14

    - From now onwards, all estimators will uniformly raise ``NotFittedError``
      (:class:`utils.validation.NotFittedError`), when any of the ``predict``
      like methods are called before the model is fit. By `Raghav RV`_.

    - Input data validation was refactored for more consistent input
      validation. The ``check_arrays`` function was replaced by ``check_array``
      and ``check_X_y``. By `Andreas Müller`_.

    - Allow ``X=None`` in the methods ``radius_neighbors``, ``kneighbors``,
      ``kneighbors_graph`` and ``radius_neighbors_graph`` in
      :class:`sklearn.neighbors.NearestNeighbors` and family. If set to None,
      then for every sample this avoids setting the sample itself as the
      first nearest neighbor. By `Manoj Kumar`_.

    - Add parameter ``include_self`` in :func:`neighbors.kneighbors_graph`
      and :func:`neighbors.radius_neighbors_graph` which has to be explicitly
      set by the user. If set to True, then the sample itself is considered
      as the first nearest neighbor.

    - `thresh` parameter is deprecated in favor of new `tol` parameter in
      :class:`GMM`, :class:`DPGMM` and :class:`VBGMM`. See `Enhancements`
      section for details. By `Hervé Bredin`_.

    - Estimators will treat input with dtype object as numeric when possible.
      By `Andreas Müller`_

    - Estimators now raise `ValueError` consistently when fitted on empty
      data (less than 1 sample or less than 1 feature for 2D input).
      By `Olivier Grisel`_.


    - The ``shuffle`` option of :class:`.linear_model.SGDClassifier`,
      :class:`linear_model.SGDRegressor`, :class:`linear_model.Perceptron`,
      :class:`linear_model.PassiveAgressiveClassifier` and
      :class:`linear_model.PassiveAgressiveRegressor` now defaults to ``True``.

    - :class:`cluster.DBSCAN` now uses a deterministic initialization. The
      `random_state` parameter is deprecated. By :user:`Erich Schubert <kno10>`.

Code Contributors
-----------------
A. Flaxman, Aaron Schumacher, Aaron Staple, abhishek thakur, Akshay, akshayah3,
Aldrian Obaja, Alexander Fabisch, Alexandre Gramfort, Alexis Mignon, Anders
Aagaard, Andreas Mueller, Andreas van Cranenburgh, Andrew Tulloch, Andrew
Walker, Antony Lee, Arnaud Joly, banilo, Barmaley.exe, Ben Davies, Benedikt
Koehler, bhsu, Boris Feld, Borja Ayerdi, Boyuan Deng, Brent Pedersen, Brian
Wignall, Brooke Osborn, Calvin Giles, Cathy Deng, Celeo, cgohlke, chebee7i,
Christian Stade-Schuldt, Christof Angermueller, Chyi-Kwei Yau, CJ Carey,
Clemens Brunner, Daiki Aminaka, Dan Blanchard, danfrankj, Danny Sullivan, David
Fletcher, Dmitrijs Milajevs, Dougal J. Sutherland, Erich Schubert, Fabian
Pedregosa, Florian Wilhelm, floydsoft, Félix-Antoine Fortin, Gael Varoquaux,
Garrett-R, Gilles Louppe, gpassino, gwulfs, Hampus Bengtsson, Hamzeh Alsalhi,
Hanna Wallach, Harry Mavroforakis, Hasil Sharma, Helder, Herve Bredin,
Hsiang-Fu Yu, Hugues SALAMIN, Ian Gilmore, Ilambharathi Kanniah, Imran Haque,
isms, Jake VanderPlas, Jan Dlabal, Jan Hendrik Metzen, Jatin Shah, Javier López
Peña, jdcaballero, Jean Kossaifi, Jeff Hammerbacher, Joel Nothman, Jonathan
Helmus, Joseph, Kaicheng Zhang, Kevin Markham, Kyle Beauchamp, Kyle Kastner,
Lagacherie Matthieu, Lars Buitinck, Laurent Direr, leepei, Loic Esteve, Luis
Pedro Coelho, Lukas Michelbacher, maheshakya, Manoj Kumar, Manuel, Mario
Michael Krell, Martin, Martin Billinger, Martin Ku, Mateusz Susik, Mathieu
Blondel, Matt Pico, Matt Terry, Matteo Visconti dOC, Matti Lyra, Max Linke,
Mehdi Cherti, Michael Bommarito, Michael Eickenberg, Michal Romaniuk, MLG,
mr.Shu, Nelle Varoquaux, Nicola Montecchio, Nicolas, Nikolay Mayorov, Noel
Dawe, Okal Billy, Olivier Grisel, Óscar Nájera, Paolo Puggioni, Peter
Prettenhofer, Pratap Vardhan, pvnguyen, queqichao, Rafael Carrascosa, Raghav R
V, Rahiel Kasim, Randall Mason, Rob Zinkov, Robert Bradshaw, Saket Choudhary,
Sam Nicholls, Samuel Charron, Saurabh Jha, sethdandridge, sinhrks, snuderl,
Stefan Otte, Stefan van der Walt, Steve Tjoa, swu, Sylvain Zimmer, tejesh95,
terrycojones, Thomas Delteil, Thomas Unterthiner, Tomas Kazmar, trevorstephens,
tttthomasssss, Tzu-Ming Kuo, ugurcaliskan, ugurthemaster, Vinayak Mehta,
Vincent Dubourg, Vjacheslav Murashkin, Vlad Niculae, wadawson, Wei Xue, Will
Lamond, Wu Jiang, x0l, Xinfan Meng, Yan Yi, Yu-Chin

.. _changes_0_15_2:

Version 0.15.2
==============

**September 4, 2014**

Bug fixes
---------

  - Fixed handling of the ``p`` parameter of the Minkowski distance that was
    previously ignored in nearest neighbors models. By :user:`Nikolay
    Mayorov <nmayorov>`.

  - Fixed duplicated alphas in :class:`linear_model.LassoLars` with early
    stopping on 32 bit Python. By `Olivier Grisel`_ and `Fabian Pedregosa`_.

  - Fixed the build under Windows when scikit-learn is built with MSVC while
    NumPy is built with MinGW. By `Olivier Grisel`_ and :user:`Federico
    Vaggi <FedericoV>`.

  - Fixed an array index overflow bug in the coordinate descent solver. By
    `Gael Varoquaux`_.

  - Better handling of numpy 1.9 deprecation warnings. By `Gael Varoquaux`_.

  - Removed unnecessary data copy in :class:`cluster.KMeans`.
    By `Gael Varoquaux`_.

  - Explicitly close open files to avoid ``ResourceWarnings`` under Python 3.
    By Calvin Giles.

  - The ``transform`` of :class:`discriminant_analysis.LinearDiscriminantAnalysis`
    now projects the input on the most discriminant directions. By Martin Billinger.

  - Fixed potential overflow in ``_tree.safe_realloc`` by `Lars Buitinck`_.

  - Performance optimization in :class:`isotonic.IsotonicRegression`.
    By Robert Bradshaw.

  - ``nose`` is non-longer a runtime dependency to import ``sklearn``, only for
    running the tests. By `Joel Nothman`_.

  - Many documentation and website fixes by `Joel Nothman`_, `Lars Buitinck`_
    :user:`Matt Pico <MattpSoftware>`, and others.

.. _changes_0_15_1:

Version 0.15.1
==============

**August 1, 2014**

Bug fixes
---------

   - Made :func:`cross_validation.cross_val_score` use
     :class:`cross_validation.KFold` instead of
     :class:`cross_validation.StratifiedKFold` on multi-output classification
     problems. By :user:`Nikolay Mayorov <nmayorov>`.

   - Support unseen labels :class:`preprocessing.LabelBinarizer` to restore
     the default behavior of 0.14.1 for backward compatibility. By
     :user:`Hamzeh Alsalhi <hamsal>`.

   - Fixed the :class:`cluster.KMeans` stopping criterion that prevented early
     convergence detection. By Edward Raff and `Gael Varoquaux`_.

   - Fixed the behavior of :class:`multiclass.OneVsOneClassifier`.
     in case of ties at the per-class vote level by computing the correct
     per-class sum of prediction scores. By `Andreas Müller`_.

   - Made :func:`cross_validation.cross_val_score` and
     :class:`grid_search.GridSearchCV` accept Python lists as input data.
     This is especially useful for cross-validation and model selection of
     text processing pipelines. By `Andreas Müller`_.

   - Fixed data input checks of most estimators to accept input data that
     implements the NumPy ``__array__`` protocol. This is the case for
     for ``pandas.Series`` and ``pandas.DataFrame`` in recent versions of
     pandas. By `Gael Varoquaux`_.

   - Fixed a regression for :class:`linear_model.SGDClassifier` with
     ``class_weight="auto"`` on data with non-contiguous labels. By
     `Olivier Grisel`_.


.. _changes_0_15:

Version 0.15
============

**July 15, 2014**

Highlights
-----------

   - Many speed and memory improvements all across the code

   - Huge speed and memory improvements to random forests (and extra
     trees) that also benefit better from parallel computing.

   - Incremental fit to :class:`BernoulliRBM <neural_network.BernoulliRBM>`

   - Added :class:`cluster.AgglomerativeClustering` for hierarchical
     agglomerative clustering with average linkage, complete linkage and
     ward strategies.

   - Added :class:`linear_model.RANSACRegressor` for robust regression
     models.

   - Added dimensionality reduction with :class:`manifold.TSNE` which can be
     used to visualize high-dimensional data.


Changelog
---------

New features
............

   - Added :class:`ensemble.BaggingClassifier` and
     :class:`ensemble.BaggingRegressor` meta-estimators for ensembling
     any kind of base estimator. See the :ref:`Bagging <bagging>` section of
     the user guide for details and examples. By `Gilles Louppe`_.

   - New unsupervised feature selection algorithm
     :class:`feature_selection.VarianceThreshold`, by `Lars Buitinck`_.

   - Added :class:`linear_model.RANSACRegressor` meta-estimator for the robust
     fitting of regression models. By :user:`Johannes Schönberger <ahojnnes>`.

   - Added :class:`cluster.AgglomerativeClustering` for hierarchical
     agglomerative clustering with average linkage, complete linkage and
     ward strategies, by  `Nelle Varoquaux`_ and `Gael Varoquaux`_.

   - Shorthand constructors :func:`pipeline.make_pipeline` and
     :func:`pipeline.make_union` were added by `Lars Buitinck`_.

   - Shuffle option for :class:`cross_validation.StratifiedKFold`.
     By :user:`Jeffrey Blackburne <jblackburne>`.

   - Incremental learning (``partial_fit``) for Gaussian Naive Bayes by
     Imran Haque.

   - Added ``partial_fit`` to :class:`BernoulliRBM
     <neural_network.BernoulliRBM>`
     By :user:`Danny Sullivan <dsullivan7>`.

   - Added :func:`learning_curve <learning_curve.learning_curve>` utility to
     chart performance with respect to training size. See
     :ref:`sphx_glr_auto_examples_model_selection_plot_learning_curve.py`. By Alexander Fabisch.

   - Add positive option in :class:`LassoCV <linear_model.LassoCV>` and
     :class:`ElasticNetCV <linear_model.ElasticNetCV>`.
     By Brian Wignall and `Alexandre Gramfort`_.

   - Added :class:`linear_model.MultiTaskElasticNetCV` and
     :class:`linear_model.MultiTaskLassoCV`. By `Manoj Kumar`_.

   - Added :class:`manifold.TSNE`. By Alexander Fabisch.

Enhancements
............

   - Add sparse input support to :class:`ensemble.AdaBoostClassifier` and
     :class:`ensemble.AdaBoostRegressor` meta-estimators.
     By :user:`Hamzeh Alsalhi <hamsal>`.

   - Memory improvements of decision trees, by `Arnaud Joly`_.

   - Decision trees can now be built in best-first manner by using ``max_leaf_nodes``
     as the stopping criteria. Refactored the tree code to use either a
     stack or a priority queue for tree building.
     By `Peter Prettenhofer`_ and `Gilles Louppe`_.

   - Decision trees can now be fitted on fortran- and c-style arrays, and
     non-continuous arrays without the need to make a copy.
     If the input array has a different dtype than ``np.float32``, a fortran-
     style copy will be made since fortran-style memory layout has speed
     advantages. By `Peter Prettenhofer`_ and `Gilles Louppe`_.

   - Speed improvement of regression trees by optimizing the
     the computation of the mean square error criterion. This lead
     to speed improvement of the tree, forest and gradient boosting tree
     modules. By `Arnaud Joly`_

   - The ``img_to_graph`` and ``grid_tograph`` functions in
     :mod:`sklearn.feature_extraction.image` now return ``np.ndarray``
     instead of ``np.matrix`` when ``return_as=np.ndarray``.  See the
     Notes section for more information on compatibility.

   - Changed the internal storage of decision trees to use a struct array.
     This fixed some small bugs, while improving code and providing a small
     speed gain. By `Joel Nothman`_.

   - Reduce memory usage and overhead when fitting and predicting with forests
     of randomized trees in parallel with ``n_jobs != 1`` by leveraging new
     threading backend of joblib 0.8 and releasing the GIL in the tree fitting
     Cython code.  By `Olivier Grisel`_ and `Gilles Louppe`_.

   - Speed improvement of the :mod:`sklearn.ensemble.gradient_boosting` module.
     By `Gilles Louppe`_ and `Peter Prettenhofer`_.

   - Various enhancements to the  :mod:`sklearn.ensemble.gradient_boosting`
     module: a ``warm_start`` argument to fit additional trees,
     a ``max_leaf_nodes`` argument to fit GBM style trees,
     a ``monitor`` fit argument to inspect the estimator during training, and
     refactoring of the verbose code. By `Peter Prettenhofer`_.

   - Faster :class:`sklearn.ensemble.ExtraTrees` by caching feature values.
     By `Arnaud Joly`_.

   - Faster depth-based tree building algorithm such as decision tree,
     random forest, extra trees or gradient tree boosting (with depth based
     growing strategy) by avoiding trying to split on found constant features
     in the sample subset. By `Arnaud Joly`_.

   - Add ``min_weight_fraction_leaf`` pre-pruning parameter to tree-based
     methods: the minimum weighted fraction of the input samples required to be
     at a leaf node. By `Noel Dawe`_.

   - Added :func:`metrics.pairwise_distances_argmin_min`, by Philippe Gervais.

   - Added predict method to :class:`cluster.AffinityPropagation` and
     :class:`cluster.MeanShift`, by `Mathieu Blondel`_.

   - Vector and matrix multiplications have been optimised throughout the
     library by :user:`Denis Engemann <dengemann>`, and `Alexandre Gramfort`_.
     In particular, they should take less memory with older NumPy versions
     (prior to 1.7.2).

   - Precision-recall and ROC examples now use train_test_split, and have more
     explanation of why these metrics are useful. By `Kyle Kastner`_

   - The training algorithm for :class:`decomposition.NMF` is faster for
     sparse matrices and has much lower memory complexity, meaning it will
     scale up gracefully to large datasets. By `Lars Buitinck`_.

   - Added svd_method option with default value to "randomized" to
     :class:`decomposition.FactorAnalysis` to save memory and
     significantly speedup computation by :user:`Denis Engemann <dengemann>`, and
     `Alexandre Gramfort`_.

   - Changed :class:`cross_validation.StratifiedKFold` to try and
     preserve as much of the original ordering of samples as possible so as
     not to hide overfitting on datasets with a non-negligible level of
     samples dependency.
     By `Daniel Nouri`_ and `Olivier Grisel`_.

   - Add multi-output support to :class:`gaussian_process.GaussianProcess`
     by John Novak.

   - Support for precomputed distance matrices in nearest neighbor estimators
     by `Robert Layton`_ and `Joel Nothman`_.

   - Norm computations optimized for NumPy 1.6 and later versions by
     `Lars Buitinck`_. In particular, the k-means algorithm no longer
     needs a temporary data structure the size of its input.

   - :class:`dummy.DummyClassifier` can now be used to predict a constant
     output value. By `Manoj Kumar`_.

   - :class:`dummy.DummyRegressor` has now a strategy parameter which allows
     to predict the mean, the median of the training set or a constant
     output value. By :user:`Maheshakya Wijewardena <maheshakya>`.

   - Multi-label classification output in multilabel indicator format
     is now supported by :func:`metrics.roc_auc_score` and
     :func:`metrics.average_precision_score` by `Arnaud Joly`_.

   - Significant performance improvements (more than 100x speedup for
     large problems) in :class:`isotonic.IsotonicRegression` by
     `Andrew Tulloch`_.

   - Speed and memory usage improvements to the SGD algorithm for linear
     models: it now uses threads, not separate processes, when ``n_jobs>1``.
     By `Lars Buitinck`_.

   - Grid search and cross validation allow NaNs in the input arrays so that
     preprocessors such as :class:`preprocessing.Imputer
     <preprocessing.Imputer>` can be trained within the cross validation loop,
     avoiding potentially skewed results.

   - Ridge regression can now deal with sample weights in feature space
     (only sample space until then). By :user:`Michael Eickenberg <eickenberg>`.
     Both solutions are provided by the Cholesky solver.

   - Several classification and regression metrics now support weighted
     samples with the new ``sample_weight`` argument:
     :func:`metrics.accuracy_score`,
     :func:`metrics.zero_one_loss`,
     :func:`metrics.precision_score`,
     :func:`metrics.average_precision_score`,
     :func:`metrics.f1_score`,
     :func:`metrics.fbeta_score`,
     :func:`metrics.recall_score`,
     :func:`metrics.roc_auc_score`,
     :func:`metrics.explained_variance_score`,
     :func:`metrics.mean_squared_error`,
     :func:`metrics.mean_absolute_error`,
     :func:`metrics.r2_score`.
     By `Noel Dawe`_.

   - Speed up of the sample generator
     :func:`datasets.make_multilabel_classification`. By `Joel Nothman`_.

Documentation improvements
...........................

   - The :ref:`Working With Text Data <text_data_tutorial>` tutorial
     has now been worked in to the main documentation's tutorial section.
     Includes exercises and skeletons for tutorial presentation.
     Original tutorial created by several authors including
     `Olivier Grisel`_, Lars Buitinck and many others.
     Tutorial integration into the scikit-learn documentation
     by `Jaques Grobler`_

   - Added :ref:`Computational Performance <computational_performance>`
     documentation. Discussion and examples of prediction latency / throughput
     and different factors that have influence over speed. Additional tips for
     building faster models and choosing a relevant compromise between speed
     and predictive power.
     By :user:`Eustache Diemert <oddskool>`.

Bug fixes
.........

   - Fixed bug in :class:`decomposition.MiniBatchDictionaryLearning` :
     ``partial_fit`` was not working properly.

   - Fixed bug in :class:`linear_model.stochastic_gradient` :
     ``l1_ratio`` was used as ``(1.0 - l1_ratio)`` .

   - Fixed bug in :class:`multiclass.OneVsOneClassifier` with string
     labels

   - Fixed a bug in :class:`LassoCV <linear_model.LassoCV>` and
     :class:`ElasticNetCV <linear_model.ElasticNetCV>`: they would not
     pre-compute the Gram matrix with ``precompute=True`` or
     ``precompute="auto"`` and ``n_samples > n_features``. By `Manoj Kumar`_.

   - Fixed incorrect estimation of the degrees of freedom in
     :func:`feature_selection.f_regression` when variates are not centered.
     By :user:`Virgile Fritsch <VirgileFritsch>`.

   - Fixed a race condition in parallel processing with
     ``pre_dispatch != "all"`` (for instance, in ``cross_val_score``).
     By `Olivier Grisel`_.

   - Raise error in :class:`cluster.FeatureAgglomeration` and
     :class:`cluster.WardAgglomeration` when no samples are given,
     rather than returning meaningless clustering.

   - Fixed bug in :class:`gradient_boosting.GradientBoostingRegressor` with
     ``loss='huber'``: ``gamma`` might have not been initialized.

   - Fixed feature importances as computed with a forest of randomized trees
     when fit with ``sample_weight != None`` and/or with ``bootstrap=True``.
     By `Gilles Louppe`_.

API changes summary
-------------------

   - :mod:`sklearn.hmm` is deprecated. Its removal is planned
     for the 0.17 release.

   - Use of :class:`covariance.EllipticEnvelop` has now been removed after
     deprecation.
     Please use :class:`covariance.EllipticEnvelope` instead.

   - :class:`cluster.Ward` is deprecated. Use
     :class:`cluster.AgglomerativeClustering` instead.

   - :class:`cluster.WardClustering` is deprecated. Use
   - :class:`cluster.AgglomerativeClustering` instead.

   - :class:`cross_validation.Bootstrap` is deprecated.
     :class:`cross_validation.KFold` or
     :class:`cross_validation.ShuffleSplit` are recommended instead.

   - Direct support for the sequence of sequences (or list of lists) multilabel
     format is deprecated. To convert to and from the supported binary
     indicator matrix format, use
     :class:`MultiLabelBinarizer <preprocessing.MultiLabelBinarizer>`.
     By `Joel Nothman`_.

   - Add score method to :class:`PCA <decomposition.PCA>` following the model of
     probabilistic PCA and deprecate
     :class:`ProbabilisticPCA <decomposition.ProbabilisticPCA>` model whose
     score implementation is not correct. The computation now also exploits the
     matrix inversion lemma for faster computation. By `Alexandre Gramfort`_.

   - The score method of :class:`FactorAnalysis <decomposition.FactorAnalysis>`
     now returns the average log-likelihood of the samples. Use score_samples
     to get log-likelihood of each sample. By `Alexandre Gramfort`_.

   - Generating boolean masks (the setting ``indices=False``)
     from cross-validation generators is deprecated.
     Support for masks will be removed in 0.17.
     The generators have produced arrays of indices by default since 0.10.
     By `Joel Nothman`_.

   - 1-d arrays containing strings with ``dtype=object`` (as used in Pandas)
     are now considered valid classification targets. This fixes a regression
     from version 0.13 in some classifiers. By `Joel Nothman`_.

   - Fix wrong ``explained_variance_ratio_`` attribute in
     :class:`RandomizedPCA <decomposition.RandomizedPCA>`.
     By `Alexandre Gramfort`_.

   - Fit alphas for each ``l1_ratio`` instead of ``mean_l1_ratio`` in
     :class:`linear_model.ElasticNetCV` and :class:`linear_model.LassoCV`.
     This changes the shape of ``alphas_`` from ``(n_alphas,)`` to
     ``(n_l1_ratio, n_alphas)`` if the ``l1_ratio`` provided is a 1-D array like
     object of length greater than one.
     By `Manoj Kumar`_.

   - Fix :class:`linear_model.ElasticNetCV` and :class:`linear_model.LassoCV`
     when fitting intercept and input data is sparse. The automatic grid
     of alphas was not computed correctly and the scaling with normalize
     was wrong. By `Manoj Kumar`_.

   - Fix wrong maximal number of features drawn (``max_features``) at each split
     for decision trees, random forests and gradient tree boosting.
     Previously, the count for the number of drawn features started only after
     one non constant features in the split. This bug fix will affect
     computational and generalization performance of those algorithms in the
     presence of constant features. To get back previous generalization
     performance, you should modify the value of ``max_features``.
     By `Arnaud Joly`_.

   - Fix wrong maximal number of features drawn (``max_features``) at each split
     for :class:`ensemble.ExtraTreesClassifier` and
     :class:`ensemble.ExtraTreesRegressor`. Previously, only non constant
     features in the split was counted as drawn. Now constant features are
     counted as drawn. Furthermore at least one feature must be non constant
     in order to make a valid split. This bug fix will affect
     computational and generalization performance of extra trees in the
     presence of constant features. To get back previous generalization
     performance, you should modify the value of ``max_features``.
     By `Arnaud Joly`_.

   - Fix :func:`utils.compute_class_weight` when ``class_weight=="auto"``.
     Previously it was broken for input of non-integer ``dtype`` and the
     weighted array that was returned was wrong. By `Manoj Kumar`_.

   - Fix :class:`cross_validation.Bootstrap` to return ``ValueError``
     when ``n_train + n_test > n``. By :user:`Ronald Phlypo <rphlypo>`.


People
------

List of contributors for release 0.15 by number of commits.

* 312	Olivier Grisel
* 275	Lars Buitinck
* 221	Gael Varoquaux
* 148	Arnaud Joly
* 134	Johannes Schönberger
* 119	Gilles Louppe
* 113	Joel Nothman
* 111	Alexandre Gramfort
*  95	Jaques Grobler
*  89	Denis Engemann
*  83	Peter Prettenhofer
*  83	Alexander Fabisch
*  62	Mathieu Blondel
*  60	Eustache Diemert
*  60	Nelle Varoquaux
*  49	Michael Bommarito
*  45	Manoj-Kumar-S
*  28	Kyle Kastner
*  26	Andreas Mueller
*  22	Noel Dawe
*  21	Maheshakya Wijewardena
*  21	Brooke Osborn
*  21	Hamzeh Alsalhi
*  21	Jake VanderPlas
*  21	Philippe Gervais
*  19	Bala Subrahmanyam Varanasi
*  12	Ronald Phlypo
*  10	Mikhail Korobov
*   8	Thomas Unterthiner
*   8	Jeffrey Blackburne
*   8	eltermann
*   8	bwignall
*   7	Ankit Agrawal
*   7	CJ Carey
*   6	Daniel Nouri
*   6	Chen Liu
*   6	Michael Eickenberg
*   6	ugurthemaster
*   5	Aaron Schumacher
*   5	Baptiste Lagarde
*   5	Rajat Khanduja
*   5	Robert McGibbon
*   5	Sergio Pascual
*   4	Alexis Metaireau
*   4	Ignacio Rossi
*   4	Virgile Fritsch
*   4	Sebastian Säger
*   4	Ilambharathi Kanniah
*   4	sdenton4
*   4	Robert Layton
*   4	Alyssa
*   4	Amos Waterland
*   3	Andrew Tulloch
*   3	murad
*   3	Steven Maude
*   3	Karol Pysniak
*   3	Jacques Kvam
*   3	cgohlke
*   3	cjlin
*   3	Michael Becker
*   3	hamzeh
*   3	Eric Jacobsen
*   3	john collins
*   3	kaushik94
*   3	Erwin Marsi
*   2	csytracy
*   2	LK
*   2	Vlad Niculae
*   2	Laurent Direr
*   2	Erik Shilts
*   2	Raul Garreta
*   2	Yoshiki Vázquez Baeza
*   2	Yung Siang Liau
*   2	abhishek thakur
*   2	James Yu
*   2	Rohit Sivaprasad
*   2	Roland Szabo
*   2	amormachine
*   2	Alexis Mignon
*   2	Oscar Carlsson
*   2	Nantas Nardelli
*   2	jess010
*   2	kowalski87
*   2	Andrew Clegg
*   2	Federico Vaggi
*   2	Simon Frid
*   2	Félix-Antoine Fortin
*   1	Ralf Gommers
*   1	t-aft
*   1	Ronan Amicel
*   1	Rupesh Kumar Srivastava
*   1	Ryan Wang
*   1	Samuel Charron
*   1	Samuel St-Jean
*   1	Fabian Pedregosa
*   1	Skipper Seabold
*   1	Stefan Walk
*   1	Stefan van der Walt
*   1	Stephan Hoyer
*   1	Allen Riddell
*   1	Valentin Haenel
*   1	Vijay Ramesh
*   1	Will Myers
*   1	Yaroslav Halchenko
*   1	Yoni Ben-Meshulam
*   1	Yury V. Zaytsev
*   1	adrinjalali
*   1	ai8rahim
*   1	alemagnani
*   1	alex
*   1	benjamin wilson
*   1	chalmerlowe
*   1	dzikie drożdże
*   1	jamestwebber
*   1	matrixorz
*   1	popo
*   1	samuela
*   1	François Boulogne
*   1	Alexander Measure
*   1	Ethan White
*   1	Guilherme Trein
*   1	Hendrik Heuer
*   1	IvicaJovic
*   1	Jan Hendrik Metzen
*   1	Jean Michel Rouly
*   1	Eduardo Ariño de la Rubia
*   1	Jelle Zijlstra
*   1	Eddy L O Jansson
*   1	Denis
*   1	John
*   1	John Schmidt
*   1	Jorge Cañardo Alastuey
*   1	Joseph Perla
*   1	Joshua Vredevoogd
*   1	José Ricardo
*   1	Julien Miotte
*   1	Kemal Eren
*   1	Kenta Sato
*   1	David Cournapeau
*   1	Kyle Kelley
*   1	Daniele Medri
*   1	Laurent Luce
*   1	Laurent Pierron
*   1	Luis Pedro Coelho
*   1	DanielWeitzenfeld
*   1	Craig Thompson
*   1	Chyi-Kwei Yau
*   1	Matthew Brett
*   1	Matthias Feurer
*   1	Max Linke
*   1	Chris Filo Gorgolewski
*   1	Charles Earl
*   1	Michael Hanke
*   1	Michele Orrù
*   1	Bryan Lunt
*   1	Brian Kearns
*   1	Paul Butler
*   1	Paweł Mandera
*   1	Peter
*   1	Andrew Ash
*   1	Pietro Zambelli
*   1	staubda


.. _changes_0_14:

Version 0.14
===============

**August 7, 2013**

Changelog
---------

   - Missing values with sparse and dense matrices can be imputed with the
     transformer :class:`preprocessing.Imputer` by `Nicolas Trésegnie`_.

   - The core implementation of decisions trees has been rewritten from
     scratch, allowing for faster tree induction and lower memory
     consumption in all tree-based estimators. By `Gilles Louppe`_.

   - Added :class:`ensemble.AdaBoostClassifier` and
     :class:`ensemble.AdaBoostRegressor`, by `Noel Dawe`_  and
     `Gilles Louppe`_. See the :ref:`AdaBoost <adaboost>` section of the user
     guide for details and examples.

   - Added :class:`grid_search.RandomizedSearchCV` and
     :class:`grid_search.ParameterSampler` for randomized hyperparameter
     optimization. By `Andreas Müller`_.

   - Added :ref:`biclustering <biclustering>` algorithms
     (:class:`sklearn.cluster.bicluster.SpectralCoclustering` and
     :class:`sklearn.cluster.bicluster.SpectralBiclustering`), data
     generation methods (:func:`sklearn.datasets.make_biclusters` and
     :func:`sklearn.datasets.make_checkerboard`), and scoring metrics
     (:func:`sklearn.metrics.consensus_score`). By `Kemal Eren`_.

   - Added :ref:`Restricted Boltzmann Machines<rbm>`
     (:class:`neural_network.BernoulliRBM`). By `Yann Dauphin`_.

   - Python 3 support by :user:`Justin Vincent <justinvf>`, `Lars Buitinck`_,
     :user:`Subhodeep Moitra <smoitra87>` and `Olivier Grisel`_. All tests now pass under
     Python 3.3.

   - Ability to pass one penalty (alpha value) per target in
     :class:`linear_model.Ridge`, by @eickenberg and `Mathieu Blondel`_.

   - Fixed :mod:`sklearn.linear_model.stochastic_gradient.py` L2 regularization
     issue (minor practical significance).
     By :user:`Norbert Crombach <norbert>` and `Mathieu Blondel`_ .

   - Added an interactive version of `Andreas Müller`_'s
     `Machine Learning Cheat Sheet (for scikit-learn)
     <http://peekaboo-vision.blogspot.de/2013/01/machine-learning-cheat-sheet-for-scikit.html>`_
     to the documentation. See :ref:`Choosing the right estimator <ml_map>`.
     By `Jaques Grobler`_.

   - :class:`grid_search.GridSearchCV` and
     :func:`cross_validation.cross_val_score` now support the use of advanced
     scoring function such as area under the ROC curve and f-beta scores.
     See :ref:`scoring_parameter` for details. By `Andreas Müller`_
     and `Lars Buitinck`_.
     Passing a function from :mod:`sklearn.metrics` as ``score_func`` is
     deprecated.

   - Multi-label classification output is now supported by
     :func:`metrics.accuracy_score`, :func:`metrics.zero_one_loss`,
     :func:`metrics.f1_score`, :func:`metrics.fbeta_score`,
     :func:`metrics.classification_report`,
     :func:`metrics.precision_score` and :func:`metrics.recall_score`
     by `Arnaud Joly`_.

   - Two new metrics :func:`metrics.hamming_loss` and
     :func:`metrics.jaccard_similarity_score`
     are added with multi-label support by `Arnaud Joly`_.

   - Speed and memory usage improvements in
     :class:`feature_extraction.text.CountVectorizer` and
     :class:`feature_extraction.text.TfidfVectorizer`,
     by Jochen Wersdörfer and Roman Sinayev.

   - The ``min_df`` parameter in
     :class:`feature_extraction.text.CountVectorizer` and
     :class:`feature_extraction.text.TfidfVectorizer`, which used to be 2,
     has been reset to 1 to avoid unpleasant surprises (empty vocabularies)
     for novice users who try it out on tiny document collections.
     A value of at least 2 is still recommended for practical use.

   - :class:`svm.LinearSVC`, :class:`linear_model.SGDClassifier` and
     :class:`linear_model.SGDRegressor` now have a ``sparsify`` method that
     converts their ``coef_`` into a sparse matrix, meaning stored models
     trained using these estimators can be made much more compact.

   - :class:`linear_model.SGDClassifier` now produces multiclass probability
     estimates when trained under log loss or modified Huber loss.

   - Hyperlinks to documentation in example code on the website by
     :user:`Martin Luessi <mluessi>`.

   - Fixed bug in :class:`preprocessing.MinMaxScaler` causing incorrect scaling
     of the features for non-default ``feature_range`` settings. By `Andreas
     Müller`_.

   - ``max_features`` in :class:`tree.DecisionTreeClassifier`,
     :class:`tree.DecisionTreeRegressor` and all derived ensemble estimators
     now supports percentage values. By `Gilles Louppe`_.

   - Performance improvements in :class:`isotonic.IsotonicRegression` by
     `Nelle Varoquaux`_.

   - :func:`metrics.accuracy_score` has an option normalize to return
     the fraction or the number of correctly classified sample
     by `Arnaud Joly`_.

   - Added :func:`metrics.log_loss` that computes log loss, aka cross-entropy
     loss. By Jochen Wersdörfer and `Lars Buitinck`_.

   - A bug that caused :class:`ensemble.AdaBoostClassifier`'s to output
     incorrect probabilities has been fixed.

   - Feature selectors now share a mixin providing consistent ``transform``,
     ``inverse_transform`` and ``get_support`` methods. By `Joel Nothman`_.

   - A fitted :class:`grid_search.GridSearchCV` or
     :class:`grid_search.RandomizedSearchCV` can now generally be pickled.
     By `Joel Nothman`_.

   - Refactored and vectorized implementation of :func:`metrics.roc_curve`
     and :func:`metrics.precision_recall_curve`. By `Joel Nothman`_.

   - The new estimator :class:`sklearn.decomposition.TruncatedSVD`
     performs dimensionality reduction using SVD on sparse matrices,
     and can be used for latent semantic analysis (LSA).
     By `Lars Buitinck`_.

   - Added self-contained example of out-of-core learning on text data
     :ref:`sphx_glr_auto_examples_applications_plot_out_of_core_classification.py`.
     By :user:`Eustache Diemert <oddskool>`.

   - The default number of components for
     :class:`sklearn.decomposition.RandomizedPCA` is now correctly documented
     to be ``n_features``. This was the default behavior, so programs using it
     will continue to work as they did.

   - :class:`sklearn.cluster.KMeans` now fits several orders of magnitude
     faster on sparse data (the speedup depends on the sparsity). By
     `Lars Buitinck`_.

   - Reduce memory footprint of FastICA by :user:`Denis Engemann <dengemann>` and
     `Alexandre Gramfort`_.

   - Verbose output in :mod:`sklearn.ensemble.gradient_boosting` now uses
     a column format and prints progress in decreasing frequency.
     It also shows the remaining time. By `Peter Prettenhofer`_.

   - :mod:`sklearn.ensemble.gradient_boosting` provides out-of-bag improvement
     :attr:`~sklearn.ensemble.GradientBoostingRegressor.oob_improvement_`
     rather than the OOB score for model selection. An example that shows
     how to use OOB estimates to select the number of trees was added.
     By `Peter Prettenhofer`_.

   - Most metrics now support string labels for multiclass classification
     by `Arnaud Joly`_ and `Lars Buitinck`_.

   - New OrthogonalMatchingPursuitCV class by `Alexandre Gramfort`_
     and `Vlad Niculae`_.

   - Fixed a bug in :class:`sklearn.covariance.GraphLassoCV`: the
     'alphas' parameter now works as expected when given a list of
     values. By Philippe Gervais.

   - Fixed an important bug in :class:`sklearn.covariance.GraphLassoCV`
     that prevented all folds provided by a CV object to be used (only
     the first 3 were used). When providing a CV object, execution
     time may thus increase significantly compared to the previous
     version (bug results are correct now). By Philippe Gervais.

   - :class:`cross_validation.cross_val_score` and the :mod:`grid_search`
     module is now tested with multi-output data by `Arnaud Joly`_.

   - :func:`datasets.make_multilabel_classification` can now return
     the output in label indicator multilabel format  by `Arnaud Joly`_.

   - K-nearest neighbors, :class:`neighbors.KNeighborsRegressor`
     and :class:`neighbors.RadiusNeighborsRegressor`,
     and radius neighbors, :class:`neighbors.RadiusNeighborsRegressor` and
     :class:`neighbors.RadiusNeighborsClassifier` support multioutput data
     by `Arnaud Joly`_.

   - Random state in LibSVM-based estimators (:class:`svm.SVC`, :class:`NuSVC`,
     :class:`OneClassSVM`, :class:`svm.SVR`, :class:`svm.NuSVR`) can now be
     controlled.  This is useful to ensure consistency in the probability
     estimates for the classifiers trained with ``probability=True``. By
     `Vlad Niculae`_.

   - Out-of-core learning support for discrete naive Bayes classifiers
     :class:`sklearn.naive_bayes.MultinomialNB` and
     :class:`sklearn.naive_bayes.BernoulliNB` by adding the ``partial_fit``
     method by `Olivier Grisel`_.

   - New website design and navigation by `Gilles Louppe`_, `Nelle Varoquaux`_,
     Vincent Michel and `Andreas Müller`_.

   - Improved documentation on :ref:`multi-class, multi-label and multi-output
     classification <multiclass>` by `Yannick Schwartz`_ and `Arnaud Joly`_.

   - Better input and error handling in the :mod:`metrics` module by
     `Arnaud Joly`_ and `Joel Nothman`_.

   - Speed optimization of the :mod:`hmm` module by :user:`Mikhail Korobov <kmike>`

   - Significant speed improvements for :class:`sklearn.cluster.DBSCAN`
     by `cleverless <https://github.com/cleverless>`_


API changes summary
-------------------

   - The :func:`auc_score` was renamed :func:`roc_auc_score`.

   - Testing scikit-learn with ``sklearn.test()`` is deprecated. Use
     ``nosetests sklearn`` from the command line.

   - Feature importances in :class:`tree.DecisionTreeClassifier`,
     :class:`tree.DecisionTreeRegressor` and all derived ensemble estimators
     are now computed on the fly when accessing  the ``feature_importances_``
     attribute. Setting ``compute_importances=True`` is no longer required.
     By `Gilles Louppe`_.

   - :class:`linear_model.lasso_path` and
     :class:`linear_model.enet_path` can return its results in the same
     format as that of :class:`linear_model.lars_path`. This is done by
     setting the ``return_models`` parameter to ``False``. By
     `Jaques Grobler`_ and `Alexandre Gramfort`_

   - :class:`grid_search.IterGrid` was renamed to
     :class:`grid_search.ParameterGrid`.

   - Fixed bug in :class:`KFold` causing imperfect class balance in some
     cases. By `Alexandre Gramfort`_ and Tadej Janež.

   - :class:`sklearn.neighbors.BallTree` has been refactored, and a
     :class:`sklearn.neighbors.KDTree` has been
     added which shares the same interface.  The Ball Tree now works with
     a wide variety of distance metrics.  Both classes have many new
     methods, including single-tree and dual-tree queries, breadth-first
     and depth-first searching, and more advanced queries such as
     kernel density estimation and 2-point correlation functions.
     By `Jake Vanderplas`_

   - Support for scipy.spatial.cKDTree within neighbors queries has been
     removed, and the functionality replaced with the new :class:`KDTree`
     class.

   - :class:`sklearn.neighbors.KernelDensity` has been added, which performs
     efficient kernel density estimation with a variety of kernels.

   - :class:`sklearn.decomposition.KernelPCA` now always returns output with
     ``n_components`` components, unless the new parameter ``remove_zero_eig``
     is set to ``True``. This new behavior is consistent with the way
     kernel PCA was always documented; previously, the removal of components
     with zero eigenvalues was tacitly performed on all data.

   - ``gcv_mode="auto"`` no longer tries to perform SVD on a densified
     sparse matrix in :class:`sklearn.linear_model.RidgeCV`.

   - Sparse matrix support in :class:`sklearn.decomposition.RandomizedPCA`
     is now deprecated in favor of the new ``TruncatedSVD``.

   - :class:`cross_validation.KFold` and
     :class:`cross_validation.StratifiedKFold` now enforce `n_folds >= 2`
     otherwise a ``ValueError`` is raised. By `Olivier Grisel`_.

   - :func:`datasets.load_files`'s ``charset`` and ``charset_errors``
     parameters were renamed ``encoding`` and ``decode_errors``.

   - Attribute ``oob_score_`` in :class:`sklearn.ensemble.GradientBoostingRegressor`
     and :class:`sklearn.ensemble.GradientBoostingClassifier`
     is deprecated and has been replaced by ``oob_improvement_`` .

   - Attributes in OrthogonalMatchingPursuit have been deprecated
     (copy_X, Gram, ...) and precompute_gram renamed precompute
     for consistency. See #2224.

   - :class:`sklearn.preprocessing.StandardScaler` now converts integer input
     to float, and raises a warning. Previously it rounded for dense integer
     input.

   - :class:`sklearn.multiclass.OneVsRestClassifier` now has a
     ``decision_function`` method. This will return the distance of each
     sample from the decision boundary for each class, as long as the
     underlying estimators implement the ``decision_function`` method.
     By `Kyle Kastner`_.

   - Better input validation, warning on unexpected shapes for y.

People
------
List of contributors for release 0.14 by number of commits.

 * 277  Gilles Louppe
 * 245  Lars Buitinck
 * 187  Andreas Mueller
 * 124  Arnaud Joly
 * 112  Jaques Grobler
 * 109  Gael Varoquaux
 * 107  Olivier Grisel
 * 102  Noel Dawe
 *  99  Kemal Eren
 *  79  Joel Nothman
 *  75  Jake VanderPlas
 *  73  Nelle Varoquaux
 *  71  Vlad Niculae
 *  65  Peter Prettenhofer
 *  64  Alexandre Gramfort
 *  54  Mathieu Blondel
 *  38  Nicolas Trésegnie
 *  35  eustache
 *  27  Denis Engemann
 *  25  Yann N. Dauphin
 *  19  Justin Vincent
 *  17  Robert Layton
 *  15  Doug Coleman
 *  14  Michael Eickenberg
 *  13  Robert Marchman
 *  11  Fabian Pedregosa
 *  11  Philippe Gervais
 *  10  Jim Holmström
 *  10  Tadej Janež
 *  10  syhw
 *   9  Mikhail Korobov
 *   9  Steven De Gryze
 *   8  sergeyf
 *   7  Ben Root
 *   7  Hrishikesh Huilgolkar
 *   6  Kyle Kastner
 *   6  Martin Luessi
 *   6  Rob Speer
 *   5  Federico Vaggi
 *   5  Raul Garreta
 *   5  Rob Zinkov
 *   4  Ken Geis
 *   3  A. Flaxman
 *   3  Denton Cockburn
 *   3  Dougal Sutherland
 *   3  Ian Ozsvald
 *   3  Johannes Schönberger
 *   3  Robert McGibbon
 *   3  Roman Sinayev
 *   3  Szabo Roland
 *   2  Diego Molla
 *   2  Imran Haque
 *   2  Jochen Wersdörfer
 *   2  Sergey Karayev
 *   2  Yannick Schwartz
 *   2  jamestwebber
 *   1  Abhijeet Kolhe
 *   1  Alexander Fabisch
 *   1  Bastiaan van den Berg
 *   1  Benjamin Peterson
 *   1  Daniel Velkov
 *   1  Fazlul Shahriar
 *   1  Felix Brockherde
 *   1  Félix-Antoine Fortin
 *   1  Harikrishnan S
 *   1  Jack Hale
 *   1  JakeMick
 *   1  James McDermott
 *   1  John Benediktsson
 *   1  John Zwinck
 *   1  Joshua Vredevoogd
 *   1  Justin Pati
 *   1  Kevin Hughes
 *   1  Kyle Kelley
 *   1  Matthias Ekman
 *   1  Miroslav Shubernetskiy
 *   1  Naoki Orii
 *   1  Norbert Crombach
 *   1  Rafael Cunha de Almeida
 *   1  Rolando Espinoza La fuente
 *   1  Seamus Abshere
 *   1  Sergey Feldman
 *   1  Sergio Medina
 *   1  Stefano Lattarini
 *   1  Steve Koch
 *   1  Sturla Molden
 *   1  Thomas Jarosch
 *   1  Yaroslav Halchenko

.. _changes_0_13_1:

Version 0.13.1
==============

**February 23, 2013**

The 0.13.1 release only fixes some bugs and does not add any new functionality.

Changelog
---------

    - Fixed a testing error caused by the function :func:`cross_validation.train_test_split` being
      interpreted as a test by `Yaroslav Halchenko`_.

    - Fixed a bug in the reassignment of small clusters in the :class:`cluster.MiniBatchKMeans`
      by `Gael Varoquaux`_.

    - Fixed default value of ``gamma`` in :class:`decomposition.KernelPCA` by `Lars Buitinck`_.

    - Updated joblib to ``0.7.0d`` by `Gael Varoquaux`_.

    - Fixed scaling of the deviance in :class:`ensemble.GradientBoostingClassifier` by `Peter Prettenhofer`_.

    - Better tie-breaking in :class:`multiclass.OneVsOneClassifier` by `Andreas Müller`_.

    - Other small improvements to tests and documentation.

People
------
List of contributors for release 0.13.1 by number of commits.
 * 16  `Lars Buitinck`_
 * 12  `Andreas Müller`_
 *  8  `Gael Varoquaux`_
 *  5  Robert Marchman
 *  3  `Peter Prettenhofer`_
 *  2  Hrishikesh Huilgolkar
 *  1  Bastiaan van den Berg
 *  1  Diego Molla
 *  1  `Gilles Louppe`_
 *  1  `Mathieu Blondel`_
 *  1  `Nelle Varoquaux`_
 *  1  Rafael Cunha de Almeida
 *  1  Rolando Espinoza La fuente
 *  1  `Vlad Niculae`_
 *  1  `Yaroslav Halchenko`_


.. _changes_0_13:

Version 0.13
============

**January 21, 2013**

New Estimator Classes
---------------------

   - :class:`dummy.DummyClassifier` and :class:`dummy.DummyRegressor`, two
     data-independent predictors by `Mathieu Blondel`_. Useful to sanity-check
     your estimators. See :ref:`dummy_estimators` in the user guide.
     Multioutput support added by `Arnaud Joly`_.

   - :class:`decomposition.FactorAnalysis`, a transformer implementing the
     classical factor analysis, by `Christian Osendorfer`_ and `Alexandre
     Gramfort`_. See :ref:`FA` in the user guide.

   - :class:`feature_extraction.FeatureHasher`, a transformer implementing the
     "hashing trick" for fast, low-memory feature extraction from string fields
     by `Lars Buitinck`_ and :class:`feature_extraction.text.HashingVectorizer`
     for text documents by `Olivier Grisel`_  See :ref:`feature_hashing` and
     :ref:`hashing_vectorizer` for the documentation and sample usage.

   - :class:`pipeline.FeatureUnion`, a transformer that concatenates
     results of several other transformers by `Andreas Müller`_. See
     :ref:`feature_union` in the user guide.

   - :class:`random_projection.GaussianRandomProjection`,
     :class:`random_projection.SparseRandomProjection` and the function
     :func:`random_projection.johnson_lindenstrauss_min_dim`. The first two are
     transformers implementing Gaussian and sparse random projection matrix
     by `Olivier Grisel`_ and `Arnaud Joly`_.
     See :ref:`random_projection` in the user guide.

   - :class:`kernel_approximation.Nystroem`, a transformer for approximating
     arbitrary kernels by `Andreas Müller`_. See
     :ref:`nystroem_kernel_approx` in the user guide.

   - :class:`preprocessing.OneHotEncoder`, a transformer that computes binary
     encodings of categorical features by `Andreas Müller`_. See
     :ref:`preprocessing_categorical_features` in the user guide.

   - :class:`linear_model.PassiveAggressiveClassifier` and
     :class:`linear_model.PassiveAggressiveRegressor`, predictors implementing
     an efficient stochastic optimization for linear models by `Rob Zinkov`_ and
     `Mathieu Blondel`_. See :ref:`passive_aggressive` in the user
     guide.

   - :class:`ensemble.RandomTreesEmbedding`, a transformer for creating high-dimensional
     sparse representations using ensembles of totally random trees by  `Andreas Müller`_.
     See :ref:`random_trees_embedding` in the user guide.

   - :class:`manifold.SpectralEmbedding` and function
     :func:`manifold.spectral_embedding`, implementing the "laplacian
     eigenmaps" transformation for non-linear dimensionality reduction by Wei
     Li. See :ref:`spectral_embedding` in the user guide.

   - :class:`isotonic.IsotonicRegression` by `Fabian Pedregosa`_, `Alexandre Gramfort`_
     and `Nelle Varoquaux`_,


Changelog
---------

   - :func:`metrics.zero_one_loss` (formerly ``metrics.zero_one``) now has
     option for normalized output that reports the fraction of
     misclassifications, rather than the raw number of misclassifications. By
     Kyle Beauchamp.

   - :class:`tree.DecisionTreeClassifier` and all derived ensemble models now
     support sample weighting, by `Noel Dawe`_  and `Gilles Louppe`_.

   - Speedup improvement when using bootstrap samples in forests of randomized
     trees, by `Peter Prettenhofer`_  and `Gilles Louppe`_.

   - Partial dependence plots for :ref:`gradient_boosting` in
     :func:`ensemble.partial_dependence.partial_dependence` by `Peter
     Prettenhofer`_. See :ref:`sphx_glr_auto_examples_ensemble_plot_partial_dependence.py` for an
     example.

   - The table of contents on the website has now been made expandable by
     `Jaques Grobler`_.

   - :class:`feature_selection.SelectPercentile` now breaks ties
     deterministically instead of returning all equally ranked features.

   - :class:`feature_selection.SelectKBest` and
     :class:`feature_selection.SelectPercentile` are more numerically stable
     since they use scores, rather than p-values, to rank results. This means
     that they might sometimes select different features than they did
     previously.

   - Ridge regression and ridge classification fitting with ``sparse_cg`` solver
     no longer has quadratic memory complexity, by `Lars Buitinck`_ and
     `Fabian Pedregosa`_.

   - Ridge regression and ridge classification now support a new fast solver
     called ``lsqr``, by `Mathieu Blondel`_.

   - Speed up of :func:`metrics.precision_recall_curve` by Conrad Lee.

   - Added support for reading/writing svmlight files with pairwise
     preference attribute (qid in svmlight file format) in
     :func:`datasets.dump_svmlight_file` and
     :func:`datasets.load_svmlight_file` by `Fabian Pedregosa`_.

   - Faster and more robust :func:`metrics.confusion_matrix` and
     :ref:`clustering_evaluation` by Wei Li.

   - :func:`cross_validation.cross_val_score` now works with precomputed kernels
     and affinity matrices, by `Andreas Müller`_.

   - LARS algorithm made more numerically stable with heuristics to drop
     regressors too correlated as well as to stop the path when
     numerical noise becomes predominant, by `Gael Varoquaux`_.

   - Faster implementation of :func:`metrics.precision_recall_curve` by
     Conrad Lee.

   - New kernel :class:`metrics.chi2_kernel` by `Andreas Müller`_, often used
     in computer vision applications.

   - Fix of longstanding bug in :class:`naive_bayes.BernoulliNB` fixed by
     Shaun Jackman.

   - Implemented ``predict_proba`` in :class:`multiclass.OneVsRestClassifier`,
     by Andrew Winterman.

   - Improve consistency in gradient boosting: estimators
     :class:`ensemble.GradientBoostingRegressor` and
     :class:`ensemble.GradientBoostingClassifier` use the estimator
     :class:`tree.DecisionTreeRegressor` instead of the
     :class:`tree._tree.Tree` data structure by `Arnaud Joly`_.

   - Fixed a floating point exception in the :ref:`decision trees <tree>`
     module, by Seberg.

   - Fix :func:`metrics.roc_curve` fails when y_true has only one class
     by Wei Li.

   - Add the :func:`metrics.mean_absolute_error` function which computes the
     mean absolute error. The :func:`metrics.mean_squared_error`,
     :func:`metrics.mean_absolute_error` and
     :func:`metrics.r2_score` metrics support multioutput by `Arnaud Joly`_.

   - Fixed ``class_weight`` support in :class:`svm.LinearSVC` and
     :class:`linear_model.LogisticRegression` by `Andreas Müller`_. The meaning
     of ``class_weight`` was reversed as erroneously higher weight meant less
     positives of a given class in earlier releases.

   - Improve narrative documentation and consistency in
     :mod:`sklearn.metrics` for regression and classification metrics
     by `Arnaud Joly`_.

   - Fixed a bug in :class:`sklearn.svm.SVC` when using csr-matrices with
     unsorted indices by Xinfan Meng and `Andreas Müller`_.

   - :class:`MiniBatchKMeans`: Add random reassignment of cluster centers
     with little observations attached to them, by `Gael Varoquaux`_.


API changes summary
-------------------
   - Renamed all occurrences of ``n_atoms`` to ``n_components`` for consistency.
     This applies to :class:`decomposition.DictionaryLearning`,
     :class:`decomposition.MiniBatchDictionaryLearning`,
     :func:`decomposition.dict_learning`, :func:`decomposition.dict_learning_online`.

   - Renamed all occurrences of ``max_iters`` to ``max_iter`` for consistency.
     This applies to :class:`semi_supervised.LabelPropagation` and
     :class:`semi_supervised.label_propagation.LabelSpreading`.

   - Renamed all occurrences of ``learn_rate`` to ``learning_rate`` for
     consistency in :class:`ensemble.BaseGradientBoosting` and
     :class:`ensemble.GradientBoostingRegressor`.

   - The module ``sklearn.linear_model.sparse`` is gone. Sparse matrix support
     was already integrated into the "regular" linear models.

   - :func:`sklearn.metrics.mean_square_error`, which incorrectly returned the
     accumulated error, was removed. Use ``mean_squared_error`` instead.

   - Passing ``class_weight`` parameters to ``fit`` methods is no longer
     supported. Pass them to estimator constructors instead.

   - GMMs no longer have ``decode`` and ``rvs`` methods. Use the ``score``,
     ``predict`` or ``sample`` methods instead.

   - The ``solver`` fit option in Ridge regression and classification is now
     deprecated and will be removed in v0.14. Use the constructor option
     instead.

   - :class:`feature_extraction.text.DictVectorizer` now returns sparse
     matrices in the CSR format, instead of COO.

   - Renamed ``k`` in :class:`cross_validation.KFold` and
     :class:`cross_validation.StratifiedKFold` to ``n_folds``, renamed
     ``n_bootstraps`` to ``n_iter`` in ``cross_validation.Bootstrap``.

   - Renamed all occurrences of ``n_iterations`` to ``n_iter`` for consistency.
     This applies to :class:`cross_validation.ShuffleSplit`,
     :class:`cross_validation.StratifiedShuffleSplit`,
     :func:`utils.randomized_range_finder` and :func:`utils.randomized_svd`.

   - Replaced ``rho`` in :class:`linear_model.ElasticNet` and
     :class:`linear_model.SGDClassifier` by ``l1_ratio``. The ``rho`` parameter
     had different meanings; ``l1_ratio`` was introduced to avoid confusion.
     It has the same meaning as previously ``rho`` in
     :class:`linear_model.ElasticNet` and ``(1-rho)`` in
     :class:`linear_model.SGDClassifier`.

   - :class:`linear_model.LassoLars` and :class:`linear_model.Lars` now
     store a list of paths in the case of multiple targets, rather than
     an array of paths.

   - The attribute ``gmm`` of :class:`hmm.GMMHMM` was renamed to ``gmm_``
     to adhere more strictly with the API.

   - :func:`cluster.spectral_embedding` was moved to
     :func:`manifold.spectral_embedding`.

   - Renamed ``eig_tol`` in :func:`manifold.spectral_embedding`,
     :class:`cluster.SpectralClustering` to ``eigen_tol``, renamed ``mode``
     to ``eigen_solver``.

   - Renamed ``mode`` in :func:`manifold.spectral_embedding` and
     :class:`cluster.SpectralClustering` to ``eigen_solver``.

   - ``classes_`` and ``n_classes_`` attributes of
     :class:`tree.DecisionTreeClassifier` and all derived ensemble models are
     now flat in case of single output problems and nested in case of
     multi-output problems.

   - The ``estimators_`` attribute of
     :class:`ensemble.gradient_boosting.GradientBoostingRegressor` and
     :class:`ensemble.gradient_boosting.GradientBoostingClassifier` is now an
     array of :class:'tree.DecisionTreeRegressor'.

   - Renamed ``chunk_size`` to ``batch_size`` in
     :class:`decomposition.MiniBatchDictionaryLearning` and
     :class:`decomposition.MiniBatchSparsePCA` for consistency.

   - :class:`svm.SVC` and :class:`svm.NuSVC` now provide a ``classes_``
     attribute and support arbitrary dtypes for labels ``y``.
     Also, the dtype returned by ``predict`` now reflects the dtype of
     ``y`` during ``fit`` (used to be ``np.float``).

   - Changed default test_size in :func:`cross_validation.train_test_split`
     to None, added possibility to infer ``test_size`` from ``train_size`` in
     :class:`cross_validation.ShuffleSplit` and
     :class:`cross_validation.StratifiedShuffleSplit`.

   - Renamed function :func:`sklearn.metrics.zero_one` to
     :func:`sklearn.metrics.zero_one_loss`. Be aware that the default behavior
     in :func:`sklearn.metrics.zero_one_loss` is different from
     :func:`sklearn.metrics.zero_one`: ``normalize=False`` is changed to
     ``normalize=True``.

   - Renamed function :func:`metrics.zero_one_score` to
     :func:`metrics.accuracy_score`.

   - :func:`datasets.make_circles` now has the same number of inner and outer points.

   - In the Naive Bayes classifiers, the ``class_prior`` parameter was moved
     from ``fit`` to ``__init__``.

People
------
List of contributors for release 0.13 by number of commits.

 * 364  `Andreas Müller`_
 * 143  `Arnaud Joly`_
 * 137  `Peter Prettenhofer`_
 * 131  `Gael Varoquaux`_
 * 117  `Mathieu Blondel`_
 * 108  `Lars Buitinck`_
 * 106  Wei Li
 * 101  `Olivier Grisel`_
 *  65  `Vlad Niculae`_
 *  54  `Gilles Louppe`_
 *  40  `Jaques Grobler`_
 *  38  `Alexandre Gramfort`_
 *  30  `Rob Zinkov`_
 *  19  Aymeric Masurelle
 *  18  Andrew Winterman
 *  17  `Fabian Pedregosa`_
 *  17  Nelle Varoquaux
 *  16  `Christian Osendorfer`_
 *  14  `Daniel Nouri`_
 *  13  :user:`Virgile Fritsch <VirgileFritsch>`
 *  13  syhw
 *  12  `Satrajit Ghosh`_
 *  10  Corey Lynch
 *  10  Kyle Beauchamp
 *   9  Brian Cheung
 *   9  Immanuel Bayer
 *   9  mr.Shu
 *   8  Conrad Lee
 *   8  `James Bergstra`_
 *   7  Tadej Janež
 *   6  Brian Cajes
 *   6  `Jake Vanderplas`_
 *   6  Michael
 *   6  Noel Dawe
 *   6  Tiago Nunes
 *   6  cow
 *   5  Anze
 *   5  Shiqiao Du
 *   4  Christian Jauvin
 *   4  Jacques Kvam
 *   4  Richard T. Guy
 *   4  `Robert Layton`_
 *   3  Alexandre Abraham
 *   3  Doug Coleman
 *   3  Scott Dickerson
 *   2  ApproximateIdentity
 *   2  John Benediktsson
 *   2  Mark Veronda
 *   2  Matti Lyra
 *   2  Mikhail Korobov
 *   2  Xinfan Meng
 *   1  Alejandro Weinstein
 *   1  `Alexandre Passos`_
 *   1  Christoph Deil
 *   1  Eugene Nizhibitsky
 *   1  Kenneth C. Arnold
 *   1  Luis Pedro Coelho
 *   1  Miroslav Batchkarov
 *   1  Pavel
 *   1  Sebastian Berg
 *   1  Shaun Jackman
 *   1  Subhodeep Moitra
 *   1  bob
 *   1  dengemann
 *   1  emanuele
 *   1  x006


.. _changes_0_12.1:

Version 0.12.1
===============

**October 8, 2012**

The 0.12.1 release is a bug-fix release with no additional features, but is
instead a set of bug fixes

Changelog
----------

 - Improved numerical stability in spectral embedding by `Gael
   Varoquaux`_

 - Doctest under windows 64bit by `Gael Varoquaux`_

 - Documentation fixes for elastic net by `Andreas Müller`_ and
   `Alexandre Gramfort`_

 - Proper behavior with fortran-ordered NumPy arrays by `Gael Varoquaux`_

 - Make GridSearchCV work with non-CSR sparse matrix by `Lars Buitinck`_

 - Fix parallel computing in MDS by `Gael Varoquaux`_

 - Fix Unicode support in count vectorizer by `Andreas Müller`_

 - Fix MinCovDet breaking with X.shape = (3, 1) by :user:`Virgile Fritsch <VirgileFritsch>`

 - Fix clone of SGD objects by `Peter Prettenhofer`_

 - Stabilize GMM by :user:`Virgile Fritsch <VirgileFritsch>`

People
------

 *  14  `Peter Prettenhofer`_
 *  12  `Gael Varoquaux`_
 *  10  `Andreas Müller`_
 *   5  `Lars Buitinck`_
 *   3  :user:`Virgile Fritsch <VirgileFritsch>`
 *   1  `Alexandre Gramfort`_
 *   1  `Gilles Louppe`_
 *   1  `Mathieu Blondel`_

.. _changes_0_12:

Version 0.12
============

**September 4, 2012**

Changelog
---------

   - Various speed improvements of the :ref:`decision trees <tree>` module, by
     `Gilles Louppe`_.

   - :class:`ensemble.GradientBoostingRegressor` and
     :class:`ensemble.GradientBoostingClassifier` now support feature subsampling
     via the ``max_features`` argument, by `Peter Prettenhofer`_.

   - Added Huber and Quantile loss functions to
     :class:`ensemble.GradientBoostingRegressor`, by `Peter Prettenhofer`_.

   - :ref:`Decision trees <tree>` and :ref:`forests of randomized trees <forest>`
     now support multi-output classification and regression problems, by
     `Gilles Louppe`_.

   - Added :class:`preprocessing.LabelEncoder`, a simple utility class to
     normalize labels or transform non-numerical labels, by `Mathieu Blondel`_.

   - Added the epsilon-insensitive loss and the ability to make probabilistic
     predictions with the modified huber loss in :ref:`sgd`, by
     `Mathieu Blondel`_.

   - Added :ref:`multidimensional_scaling`, by Nelle Varoquaux.

   - SVMlight file format loader now detects compressed (gzip/bzip2) files and
     decompresses them on the fly, by `Lars Buitinck`_.

   - SVMlight file format serializer now preserves double precision floating
     point values, by `Olivier Grisel`_.

   - A common testing framework for all estimators was added, by `Andreas Müller`_.

   - Understandable error messages for estimators that do not accept
     sparse input by `Gael Varoquaux`_

   - Speedups in hierarchical clustering by `Gael Varoquaux`_. In
     particular building the tree now supports early stopping. This is
     useful when the number of clusters is not small compared to the
     number of samples.

   - Add MultiTaskLasso and MultiTaskElasticNet for joint feature selection,
     by `Alexandre Gramfort`_.

   - Added :func:`metrics.auc_score` and
     :func:`metrics.average_precision_score` convenience functions by `Andreas
     Müller`_.

   - Improved sparse matrix support in the :ref:`feature_selection`
     module by `Andreas Müller`_.

   - New word boundaries-aware character n-gram analyzer for the
     :ref:`text_feature_extraction` module by :user:`@kernc <kernc>`.

   - Fixed bug in spectral clustering that led to single point clusters
     by `Andreas Müller`_.

   - In :class:`feature_extraction.text.CountVectorizer`, added an option to
     ignore infrequent words, ``min_df`` by  `Andreas Müller`_.

   - Add support for multiple targets in some linear models (ElasticNet, Lasso
     and OrthogonalMatchingPursuit) by `Vlad Niculae`_ and
     `Alexandre Gramfort`_.

   - Fixes in :class:`decomposition.ProbabilisticPCA` score function by Wei Li.

   - Fixed feature importance computation in
     :ref:`gradient_boosting`.

API changes summary
-------------------

   - The old ``scikits.learn`` package has disappeared; all code should import
     from ``sklearn`` instead, which was introduced in 0.9.

   - In :func:`metrics.roc_curve`, the ``thresholds`` array is now returned
     with it's order reversed, in order to keep it consistent with the order
     of the returned ``fpr`` and ``tpr``.

   - In :class:`hmm` objects, like :class:`hmm.GaussianHMM`,
     :class:`hmm.MultinomialHMM`, etc., all parameters must be passed to the
     object when initialising it and not through ``fit``. Now ``fit`` will
     only accept the data as an input parameter.

   - For all SVM classes, a faulty behavior of ``gamma`` was fixed. Previously,
     the default gamma value was only computed the first time ``fit`` was called
     and then stored. It is now recalculated on every call to ``fit``.

   - All ``Base`` classes are now abstract meta classes so that they can not be
     instantiated.

   - :func:`cluster.ward_tree` now also returns the parent array. This is
     necessary for early-stopping in which case the tree is not
     completely built.

   - In :class:`feature_extraction.text.CountVectorizer` the parameters
     ``min_n`` and ``max_n`` were joined to the parameter ``n_gram_range`` to
     enable grid-searching both at once.

   - In :class:`feature_extraction.text.CountVectorizer`, words that appear
     only in one document are now ignored by default. To reproduce
     the previous behavior, set ``min_df=1``.

   - Fixed API inconsistency: :meth:`linear_model.SGDClassifier.predict_proba` now
     returns 2d array when fit on two classes.

   - Fixed API inconsistency: :meth:`discriminant_analysis.QuadraticDiscriminantAnalysis.decision_function`
     and :meth:`discriminant_analysis.LinearDiscriminantAnalysis.decision_function` now return 1d arrays
     when fit on two classes.

   - Grid of alphas used for fitting :class:`linear_model.LassoCV` and
     :class:`linear_model.ElasticNetCV` is now stored
     in the attribute ``alphas_`` rather than overriding the init parameter
     ``alphas``.

   - Linear models when alpha is estimated by cross-validation store
     the estimated value in the ``alpha_`` attribute rather than just
     ``alpha`` or ``best_alpha``.

   - :class:`ensemble.GradientBoostingClassifier` now supports
     :meth:`ensemble.GradientBoostingClassifier.staged_predict_proba`, and
     :meth:`ensemble.GradientBoostingClassifier.staged_predict`.

   - :class:`svm.sparse.SVC` and other sparse SVM classes are now deprecated.
     The all classes in the :ref:`svm` module now automatically select the
     sparse or dense representation base on the input.

   - All clustering algorithms now interpret the array ``X`` given to ``fit`` as
     input data, in particular :class:`cluster.SpectralClustering` and
     :class:`cluster.AffinityPropagation` which previously expected affinity matrices.

   - For clustering algorithms that take the desired number of clusters as a parameter,
     this parameter is now called ``n_clusters``.


People
------
 * 267  `Andreas Müller`_
 *  94  `Gilles Louppe`_
 *  89  `Gael Varoquaux`_
 *  79  `Peter Prettenhofer`_
 *  60  `Mathieu Blondel`_
 *  57  `Alexandre Gramfort`_
 *  52  `Vlad Niculae`_
 *  45  `Lars Buitinck`_
 *  44  Nelle Varoquaux
 *  37  `Jaques Grobler`_
 *  30  Alexis Mignon
 *  30  Immanuel Bayer
 *  27  `Olivier Grisel`_
 *  16  Subhodeep Moitra
 *  13  Yannick Schwartz
 *  12  :user:`@kernc <kernc>`
 *  11  :user:`Virgile Fritsch <VirgileFritsch>`
 *   9  Daniel Duckworth
 *   9  `Fabian Pedregosa`_
 *   9  `Robert Layton`_
 *   8  John Benediktsson
 *   7  Marko Burjek
 *   5  `Nicolas Pinto`_
 *   4  Alexandre Abraham
 *   4  `Jake Vanderplas`_
 *   3  `Brian Holt`_
 *   3  `Edouard Duchesnay`_
 *   3  Florian Hoenig
 *   3  flyingimmidev
 *   2  Francois Savard
 *   2  Hannes Schulz
 *   2  Peter Welinder
 *   2  `Yaroslav Halchenko`_
 *   2  Wei Li
 *   1  Alex Companioni
 *   1  Brandyn A. White
 *   1  Bussonnier Matthias
 *   1  Charles-Pierre Astolfi
 *   1  Dan O'Huiginn
 *   1  David Cournapeau
 *   1  Keith Goodman
 *   1  Ludwig Schwardt
 *   1  Olivier Hervieu
 *   1  Sergio Medina
 *   1  Shiqiao Du
 *   1  Tim Sheerman-Chase
 *   1  buguen



.. _changes_0_11:

Version 0.11
============

**May 7, 2012**

Changelog
---------

Highlights
.............

   - Gradient boosted regression trees (:ref:`gradient_boosting`)
     for classification and regression by `Peter Prettenhofer`_
     and `Scott White`_ .

   - Simple dict-based feature loader with support for categorical variables
     (:class:`feature_extraction.DictVectorizer`) by `Lars Buitinck`_.

   - Added Matthews correlation coefficient (:func:`metrics.matthews_corrcoef`)
     and added macro and micro average options to
     :func:`metrics.precision_score`, :func:`metrics.recall_score` and
     :func:`metrics.f1_score` by `Satrajit Ghosh`_.

   - :ref:`out_of_bag` of generalization error for :ref:`ensemble`
     by `Andreas Müller`_.

   - :ref:`randomized_l1`: Randomized sparse linear models for feature
     selection, by `Alexandre Gramfort`_ and `Gael Varoquaux`_

   - :ref:`label_propagation` for semi-supervised learning, by Clay
     Woolam. **Note** the semi-supervised API is still work in progress,
     and may change.

   - Added BIC/AIC model selection to classical :ref:`gmm` and unified
     the API with the remainder of scikit-learn, by `Bertrand Thirion`_

   - Added :class:`sklearn.cross_validation.StratifiedShuffleSplit`, which is
     a :class:`sklearn.cross_validation.ShuffleSplit` with balanced splits,
     by Yannick Schwartz.

   - :class:`sklearn.neighbors.NearestCentroid` classifier added, along with a
     ``shrink_threshold`` parameter, which implements **shrunken centroid
     classification**, by `Robert Layton`_.

Other changes
..............

   - Merged dense and sparse implementations of :ref:`sgd` module and
     exposed utility extension types for sequential
     datasets ``seq_dataset`` and weight vectors ``weight_vector``
     by `Peter Prettenhofer`_.

   - Added ``partial_fit`` (support for online/minibatch learning) and
     warm_start to the :ref:`sgd` module by `Mathieu Blondel`_.

   - Dense and sparse implementations of :ref:`svm` classes and
     :class:`linear_model.LogisticRegression` merged by `Lars Buitinck`_.

   - Regressors can now be used as base estimator in the :ref:`multiclass`
     module by `Mathieu Blondel`_.

   - Added n_jobs option to :func:`metrics.pairwise.pairwise_distances`
     and :func:`metrics.pairwise.pairwise_kernels` for parallel computation,
     by `Mathieu Blondel`_.

   - :ref:`k_means` can now be run in parallel, using the ``n_jobs`` argument
     to either :ref:`k_means` or :class:`KMeans`, by `Robert Layton`_.

   - Improved :ref:`cross_validation` and :ref:`grid_search` documentation
     and introduced the new :func:`cross_validation.train_test_split`
     helper function by `Olivier Grisel`_

   - :class:`svm.SVC` members ``coef_`` and ``intercept_`` changed sign for
     consistency with ``decision_function``; for ``kernel==linear``,
     ``coef_`` was fixed in the one-vs-one case, by `Andreas Müller`_.

   - Performance improvements to efficient leave-one-out cross-validated
     Ridge regression, esp. for the ``n_samples > n_features`` case, in
     :class:`linear_model.RidgeCV`, by Reuben Fletcher-Costin.

   - Refactoring and simplification of the :ref:`text_feature_extraction`
     API and fixed a bug that caused possible negative IDF,
     by `Olivier Grisel`_.

   - Beam pruning option in :class:`_BaseHMM` module has been removed since it
     is difficult to Cythonize. If you are interested in contributing a Cython
     version, you can use the python version in the git history as a reference.

   - Classes in :ref:`neighbors` now support arbitrary Minkowski metric for
     nearest neighbors searches. The metric can be specified by argument ``p``.

API changes summary
-------------------

   - :class:`covariance.EllipticEnvelop` is now deprecated - Please use :class:`covariance.EllipticEnvelope`
     instead.

   - ``NeighborsClassifier`` and ``NeighborsRegressor`` are gone in the module
     :ref:`neighbors`. Use the classes :class:`KNeighborsClassifier`,
     :class:`RadiusNeighborsClassifier`, :class:`KNeighborsRegressor`
     and/or :class:`RadiusNeighborsRegressor` instead.

   - Sparse classes in the :ref:`sgd` module are now deprecated.

   - In :class:`mixture.GMM`, :class:`mixture.DPGMM` and :class:`mixture.VBGMM`,
     parameters must be passed to an object when initialising it and not through
     ``fit``. Now ``fit`` will only accept the data as an input parameter.

   - methods ``rvs`` and ``decode`` in :class:`GMM` module are now deprecated.
     ``sample`` and ``score`` or ``predict`` should be used instead.

   - attribute ``_scores`` and ``_pvalues`` in univariate feature selection
     objects are now deprecated.
     ``scores_`` or ``pvalues_`` should be used instead.

   - In :class:`LogisticRegression`, :class:`LinearSVC`, :class:`SVC` and
     :class:`NuSVC`, the ``class_weight`` parameter is now an initialization
     parameter, not a parameter to fit. This makes grid searches
     over this parameter possible.

   - LFW ``data`` is now always shape ``(n_samples, n_features)`` to be
     consistent with the Olivetti faces dataset. Use ``images`` and
     ``pairs`` attribute to access the natural images shapes instead.

   - In :class:`svm.LinearSVC`, the meaning of the ``multi_class`` parameter
     changed.  Options now are ``'ovr'`` and ``'crammer_singer'``, with
     ``'ovr'`` being the default.  This does not change the default behavior
     but hopefully is less confusing.

   - Class :class:`feature_selection.text.Vectorizer` is deprecated and
     replaced by :class:`feature_selection.text.TfidfVectorizer`.

   - The preprocessor / analyzer nested structure for text feature
     extraction has been removed. All those features are
     now directly passed as flat constructor arguments
     to :class:`feature_selection.text.TfidfVectorizer` and
     :class:`feature_selection.text.CountVectorizer`, in particular the
     following parameters are now used:

       - ``analyzer`` can be ``'word'`` or ``'char'`` to switch the default
         analysis scheme, or use a specific python callable (as previously).

       - ``tokenizer`` and ``preprocessor`` have been introduced to make it
         still possible to customize those steps with the new API.

       - ``input`` explicitly control how to interpret the sequence passed to
         ``fit`` and ``predict``: filenames, file objects or direct (byte or
         Unicode) strings.

       - charset decoding is explicit and strict by default.

       - the ``vocabulary``, fitted or not is now stored in the
         ``vocabulary_`` attribute to be consistent with the project
         conventions.

   - Class :class:`feature_selection.text.TfidfVectorizer` now derives directly
     from :class:`feature_selection.text.CountVectorizer` to make grid
     search trivial.

   - methods ``rvs`` in :class:`_BaseHMM` module are now deprecated.
     ``sample`` should be used instead.

   - Beam pruning option in :class:`_BaseHMM` module is removed since it is
     difficult to be Cythonized. If you are interested, you can look in the
     history codes by git.

   - The SVMlight format loader now supports files with both zero-based and
     one-based column indices, since both occur "in the wild".

   - Arguments in class :class:`ShuffleSplit` are now consistent with
     :class:`StratifiedShuffleSplit`. Arguments ``test_fraction`` and
     ``train_fraction`` are deprecated and renamed to ``test_size`` and
     ``train_size`` and can accept both ``float`` and ``int``.

   - Arguments in class :class:`Bootstrap` are now consistent with
     :class:`StratifiedShuffleSplit`. Arguments ``n_test`` and
     ``n_train`` are deprecated and renamed to ``test_size`` and
     ``train_size`` and can accept both ``float`` and ``int``.

   - Argument ``p`` added to classes in :ref:`neighbors` to specify an
     arbitrary Minkowski metric for nearest neighbors searches.


People
------
   * 282  `Andreas Müller`_
   * 239  `Peter Prettenhofer`_
   * 198  `Gael Varoquaux`_
   * 129  `Olivier Grisel`_
   * 114  `Mathieu Blondel`_
   * 103  Clay Woolam
   *  96  `Lars Buitinck`_
   *  88  `Jaques Grobler`_
   *  82  `Alexandre Gramfort`_
   *  50  `Bertrand Thirion`_
   *  42  `Robert Layton`_
   *  28  flyingimmidev
   *  26  `Jake Vanderplas`_
   *  26  Shiqiao Du
   *  21  `Satrajit Ghosh`_
   *  17  `David Marek`_
   *  17  `Gilles Louppe`_
   *  14  `Vlad Niculae`_
   *  11  Yannick Schwartz
   *  10  `Fabian Pedregosa`_
   *   9  fcostin
   *   7  Nick Wilson
   *   5  Adrien Gaidon
   *   5  `Nicolas Pinto`_
   *   4  `David Warde-Farley`_
   *   5  Nelle Varoquaux
   *   5  Emmanuelle Gouillart
   *   3  Joonas Sillanpää
   *   3  Paolo Losi
   *   2  Charles McCarthy
   *   2  Roy Hyunjin Han
   *   2  Scott White
   *   2  ibayer
   *   1  Brandyn White
   *   1  Carlos Scheidegger
   *   1  Claire Revillet
   *   1  Conrad Lee
   *   1  `Edouard Duchesnay`_
   *   1  Jan Hendrik Metzen
   *   1  Meng Xinfan
   *   1  `Rob Zinkov`_
   *   1  Shiqiao
   *   1  Udi Weinsberg
   *   1  Virgile Fritsch
   *   1  Xinfan Meng
   *   1  Yaroslav Halchenko
   *   1  jansoe
   *   1  Leon Palafox


.. _changes_0_10:

Version 0.10
============

**January 11, 2012**

Changelog
---------

   - Python 2.5 compatibility was dropped; the minimum Python version needed
     to use scikit-learn is now 2.6.

   - :ref:`sparse_inverse_covariance` estimation using the graph Lasso, with
     associated cross-validated estimator, by `Gael Varoquaux`_

   - New :ref:`Tree <tree>` module by `Brian Holt`_, `Peter Prettenhofer`_,
     `Satrajit Ghosh`_ and `Gilles Louppe`_. The module comes with complete
     documentation and examples.

   - Fixed a bug in the RFE module by `Gilles Louppe`_ (issue #378).

   - Fixed a memory leak in :ref:`svm` module by `Brian Holt`_ (issue #367).

   - Faster tests by `Fabian Pedregosa`_ and others.

   - Silhouette Coefficient cluster analysis evaluation metric added as
     :func:`sklearn.metrics.silhouette_score` by Robert Layton.

   - Fixed a bug in :ref:`k_means` in the handling of the ``n_init`` parameter:
     the clustering algorithm used to be run ``n_init`` times but the last
     solution was retained instead of the best solution by `Olivier Grisel`_.

   - Minor refactoring in :ref:`sgd` module; consolidated dense and sparse
     predict methods; Enhanced test time performance by converting model
     parameters to fortran-style arrays after fitting (only multi-class).

   - Adjusted Mutual Information metric added as
     :func:`sklearn.metrics.adjusted_mutual_info_score` by Robert Layton.

   - Models like SVC/SVR/LinearSVC/LogisticRegression from libsvm/liblinear
     now support scaling of C regularization parameter by the number of
     samples by `Alexandre Gramfort`_.

   - New :ref:`Ensemble Methods <ensemble>` module by `Gilles Louppe`_ and
     `Brian Holt`_. The module comes with the random forest algorithm and the
     extra-trees method, along with documentation and examples.

   - :ref:`outlier_detection`: outlier and novelty detection, by
     :user:`Virgile Fritsch <VirgileFritsch>`.

   - :ref:`kernel_approximation`: a transform implementing kernel
     approximation for fast SGD on non-linear kernels by
     `Andreas Müller`_.

   - Fixed a bug due to atom swapping in :ref:`OMP` by `Vlad Niculae`_.

   - :ref:`SparseCoder` by `Vlad Niculae`_.

   - :ref:`mini_batch_kmeans` performance improvements by `Olivier Grisel`_.

   - :ref:`k_means` support for sparse matrices by `Mathieu Blondel`_.

   - Improved documentation for developers and for the :mod:`sklearn.utils`
     module, by `Jake Vanderplas`_.

   - Vectorized 20newsgroups dataset loader
     (:func:`sklearn.datasets.fetch_20newsgroups_vectorized`) by
     `Mathieu Blondel`_.

   - :ref:`multiclass` by `Lars Buitinck`_.

   - Utilities for fast computation of mean and variance for sparse matrices
     by `Mathieu Blondel`_.

   - Make :func:`sklearn.preprocessing.scale` and
     :class:`sklearn.preprocessing.Scaler` work on sparse matrices by
     `Olivier Grisel`_

   - Feature importances using decision trees and/or forest of trees,
     by `Gilles Louppe`_.

   - Parallel implementation of forests of randomized trees by
     `Gilles Louppe`_.

   - :class:`sklearn.cross_validation.ShuffleSplit` can subsample the train
     sets as well as the test sets by `Olivier Grisel`_.

   - Errors in the build of the documentation fixed by `Andreas Müller`_.


API changes summary
-------------------

Here are the code migration instructions when upgrading from scikit-learn
version 0.9:

  - Some estimators that may overwrite their inputs to save memory previously
    had ``overwrite_`` parameters; these have been replaced with ``copy_``
    parameters with exactly the opposite meaning.

    This particularly affects some of the estimators in :mod:`linear_model`.
    The default behavior is still to copy everything passed in.

  - The SVMlight dataset loader :func:`sklearn.datasets.load_svmlight_file` no
    longer supports loading two files at once; use ``load_svmlight_files``
    instead. Also, the (unused) ``buffer_mb`` parameter is gone.

  - Sparse estimators in the :ref:`sgd` module use dense parameter vector
    ``coef_`` instead of ``sparse_coef_``. This significantly improves
    test time performance.

  - The :ref:`covariance` module now has a robust estimator of
    covariance, the Minimum Covariance Determinant estimator.

  - Cluster evaluation metrics in :mod:`metrics.cluster` have been refactored
    but the changes are backwards compatible. They have been moved to the
    :mod:`metrics.cluster.supervised`, along with
    :mod:`metrics.cluster.unsupervised` which contains the Silhouette
    Coefficient.

  - The ``permutation_test_score`` function now behaves the same way as
    ``cross_val_score`` (i.e. uses the mean score across the folds.)

  - Cross Validation generators now use integer indices (``indices=True``)
    by default instead of boolean masks. This make it more intuitive to
    use with sparse matrix data.

  - The functions used for sparse coding, ``sparse_encode`` and
    ``sparse_encode_parallel`` have been combined into
    :func:`sklearn.decomposition.sparse_encode`, and the shapes of the arrays
    have been transposed for consistency with the matrix factorization setting,
    as opposed to the regression setting.

  - Fixed an off-by-one error in the SVMlight/LibSVM file format handling;
    files generated using :func:`sklearn.datasets.dump_svmlight_file` should be
    re-generated. (They should continue to work, but accidentally had one
    extra column of zeros prepended.)

  - ``BaseDictionaryLearning`` class replaced by ``SparseCodingMixin``.

  - :func:`sklearn.utils.extmath.fast_svd` has been renamed
    :func:`sklearn.utils.extmath.randomized_svd` and the default
    oversampling is now fixed to 10 additional random vectors instead
    of doubling the number of components to extract. The new behavior
    follows the reference paper.


People
------

The following people contributed to scikit-learn since last release:

   * 246  `Andreas Müller`_
   * 242  `Olivier Grisel`_
   * 220  `Gilles Louppe`_
   * 183  `Brian Holt`_
   * 166  `Gael Varoquaux`_
   * 144  `Lars Buitinck`_
   *  73  `Vlad Niculae`_
   *  65  `Peter Prettenhofer`_
   *  64  `Fabian Pedregosa`_
   *  60  Robert Layton
   *  55  `Mathieu Blondel`_
   *  52  `Jake Vanderplas`_
   *  44  Noel Dawe
   *  38  `Alexandre Gramfort`_
   *  24  :user:`Virgile Fritsch <VirgileFritsch>`
   *  23  `Satrajit Ghosh`_
   *   3  Jan Hendrik Metzen
   *   3  Kenneth C. Arnold
   *   3  Shiqiao Du
   *   3  Tim Sheerman-Chase
   *   3  `Yaroslav Halchenko`_
   *   2  Bala Subrahmanyam Varanasi
   *   2  DraXus
   *   2  Michael Eickenberg
   *   1  Bogdan Trach
   *   1  Félix-Antoine Fortin
   *   1  Juan Manuel Caicedo Carvajal
   *   1  Nelle Varoquaux
   *   1  `Nicolas Pinto`_
   *   1  Tiziano Zito
   *   1  Xinfan Meng



.. _changes_0_9:

Version 0.9
===========

**September 21, 2011**

scikit-learn 0.9 was released on September 2011, three months after the 0.8
release and includes the new modules :ref:`manifold`, :ref:`dirichlet_process`
as well as several new algorithms and documentation improvements.

This release also includes the dictionary-learning work developed by
`Vlad Niculae`_ as part of the `Google Summer of Code
<https://developers.google.com/open-source/gsoc>`_ program.



.. |banner1| image:: ./auto_examples/manifold/images/thumb/sphx_glr_plot_compare_methods_thumb.png
   :target: auto_examples/manifold/plot_compare_methods.html

.. |banner2| image:: ./auto_examples/linear_model/images/thumb/sphx_glr_plot_omp_thumb.png
   :target: auto_examples/linear_model/plot_omp.html

.. |banner3| image:: ./auto_examples/decomposition/images/thumb/sphx_glr_plot_kernel_pca_thumb.png
   :target: auto_examples/decomposition/plot_kernel_pca.html

.. |center-div| raw:: html

    <div style="text-align: center; margin: 0px 0 -5px 0;">

.. |end-div| raw:: html

    </div>


|center-div| |banner2| |banner1| |banner3| |end-div|

Changelog
---------

   - New :ref:`manifold` module by `Jake Vanderplas`_ and
     `Fabian Pedregosa`_.

   - New :ref:`Dirichlet Process <dirichlet_process>` Gaussian Mixture
     Model by `Alexandre Passos`_

   - :ref:`neighbors` module refactoring by `Jake Vanderplas`_ :
     general refactoring, support for sparse matrices in input, speed and
     documentation improvements. See the next section for a full list of API
     changes.

   - Improvements on the :ref:`feature_selection` module by
     `Gilles Louppe`_ : refactoring of the RFE classes, documentation
     rewrite, increased efficiency and minor API changes.

   - :ref:`SparsePCA` by `Vlad Niculae`_, `Gael Varoquaux`_ and
     `Alexandre Gramfort`_

   - Printing an estimator now behaves independently of architectures
     and Python version thanks to :user:`Jean Kossaifi <JeanKossaifi>`.

   - :ref:`Loader for libsvm/svmlight format <libsvm_loader>` by
     `Mathieu Blondel`_ and `Lars Buitinck`_

   - Documentation improvements: thumbnails in
     :ref:`example gallery <examples-index>` by `Fabian Pedregosa`_.

   - Important bugfixes in :ref:`svm` module (segfaults, bad
     performance) by `Fabian Pedregosa`_.

   - Added :ref:`multinomial_naive_bayes` and :ref:`bernoulli_naive_bayes`
     by `Lars Buitinck`_

   - Text feature extraction optimizations by Lars Buitinck

   - Chi-Square feature selection
     (:func:`feature_selection.univariate_selection.chi2`) by `Lars Buitinck`_.

   - :ref:`sample_generators` module refactoring by `Gilles Louppe`_

   - :ref:`multiclass` by `Mathieu Blondel`_

   - Ball tree rewrite by `Jake Vanderplas`_

   - Implementation of :ref:`dbscan` algorithm by Robert Layton

   - Kmeans predict and transform by Robert Layton

   - Preprocessing module refactoring by `Olivier Grisel`_

   - Faster mean shift by Conrad Lee

   - New ``Bootstrap``, :ref:`ShuffleSplit` and various other
     improvements in cross validation schemes by `Olivier Grisel`_ and
     `Gael Varoquaux`_

   - Adjusted Rand index and V-Measure clustering evaluation metrics by `Olivier Grisel`_

   - Added :class:`Orthogonal Matching Pursuit <linear_model.OrthogonalMatchingPursuit>` by `Vlad Niculae`_

   - Added 2D-patch extractor utilities in the :ref:`feature_extraction` module by `Vlad Niculae`_

   - Implementation of :class:`linear_model.LassoLarsCV`
     (cross-validated Lasso solver using the Lars algorithm) and
     :class:`linear_model.LassoLarsIC` (BIC/AIC model
     selection in Lars) by `Gael Varoquaux`_
     and `Alexandre Gramfort`_

   - Scalability improvements to :func:`metrics.roc_curve` by Olivier Hervieu

   - Distance helper functions :func:`metrics.pairwise.pairwise_distances`
     and :func:`metrics.pairwise.pairwise_kernels` by Robert Layton

   - :class:`Mini-Batch K-Means <cluster.MiniBatchKMeans>` by Nelle Varoquaux and Peter Prettenhofer.

   - :ref:`mldata` utilities by Pietro Berkes.

   - :ref:`olivetti_faces` by `David Warde-Farley`_.


API changes summary
-------------------

Here are the code migration instructions when upgrading from scikit-learn
version 0.8:

  - The ``scikits.learn`` package was renamed ``sklearn``. There is
    still a ``scikits.learn`` package alias for backward compatibility.

    Third-party projects with a dependency on scikit-learn 0.9+ should
    upgrade their codebase. For instance, under Linux / MacOSX just run
    (make a backup first!)::

      find -name "*.py" | xargs sed -i 's/\bscikits.learn\b/sklearn/g'

  - Estimators no longer accept model parameters as ``fit`` arguments:
    instead all parameters must be only be passed as constructor
    arguments or using the now public ``set_params`` method inherited
    from :class:`base.BaseEstimator`.

    Some estimators can still accept keyword arguments on the ``fit``
    but this is restricted to data-dependent values (e.g. a Gram matrix
    or an affinity matrix that are precomputed from the ``X`` data matrix.

  - The ``cross_val`` package has been renamed to ``cross_validation``
    although there is also a ``cross_val`` package alias in place for
    backward compatibility.

    Third-party projects with a dependency on scikit-learn 0.9+ should
    upgrade their codebase. For instance, under Linux / MacOSX just run
    (make a backup first!)::

      find -name "*.py" | xargs sed -i 's/\bcross_val\b/cross_validation/g'

  - The ``score_func`` argument of the
    ``sklearn.cross_validation.cross_val_score`` function is now expected
    to accept ``y_test`` and ``y_predicted`` as only arguments for
    classification and regression tasks or ``X_test`` for unsupervised
    estimators.

  - ``gamma`` parameter for support vector machine algorithms is set
    to ``1 / n_features`` by default, instead of ``1 / n_samples``.

  - The ``sklearn.hmm`` has been marked as orphaned: it will be removed
    from scikit-learn in version 0.11 unless someone steps up to
    contribute documentation, examples and fix lurking numerical
    stability issues.

  - ``sklearn.neighbors`` has been made into a submodule.  The two previously
    available estimators, ``NeighborsClassifier`` and ``NeighborsRegressor``
    have been marked as deprecated.  Their functionality has been divided
    among five new classes: ``NearestNeighbors`` for unsupervised neighbors
    searches, ``KNeighborsClassifier`` & ``RadiusNeighborsClassifier``
    for supervised classification problems, and ``KNeighborsRegressor``
    & ``RadiusNeighborsRegressor`` for supervised regression problems.

  - ``sklearn.ball_tree.BallTree`` has been moved to
    ``sklearn.neighbors.BallTree``.  Using the former will generate a warning.

  - ``sklearn.linear_model.LARS()`` and related classes (LassoLARS,
    LassoLARSCV, etc.) have been renamed to
    ``sklearn.linear_model.Lars()``.

  - All distance metrics and kernels in ``sklearn.metrics.pairwise`` now have a Y
    parameter, which by default is None. If not given, the result is the distance
    (or kernel similarity) between each sample in Y. If given, the result is the
    pairwise distance (or kernel similarity) between samples in X to Y.

  - ``sklearn.metrics.pairwise.l1_distance`` is now called ``manhattan_distance``,
    and by default returns the pairwise distance. For the component wise distance,
    set the parameter ``sum_over_features`` to ``False``.

Backward compatibility package aliases and other deprecated classes and
functions will be removed in version 0.11.


People
------

38 people contributed to this release.

   - 387  `Vlad Niculae`_
   - 320  `Olivier Grisel`_
   - 192  `Lars Buitinck`_
   - 179  `Gael Varoquaux`_
   - 168  `Fabian Pedregosa`_ (`INRIA`_, `Parietal Team`_)
   - 127  `Jake Vanderplas`_
   - 120  `Mathieu Blondel`_
   - 85  `Alexandre Passos`_
   - 67  `Alexandre Gramfort`_
   - 57  `Peter Prettenhofer`_
   - 56  `Gilles Louppe`_
   - 42  Robert Layton
   - 38  Nelle Varoquaux
   - 32  :user:`Jean Kossaifi <JeanKossaifi>`
   - 30  Conrad Lee
   - 22  Pietro Berkes
   - 18  andy
   - 17  David Warde-Farley
   - 12  Brian Holt
   - 11  Robert
   - 8  Amit Aides
   - 8  :user:`Virgile Fritsch <VirgileFritsch>`
   - 7  `Yaroslav Halchenko`_
   - 6  Salvatore Masecchia
   - 5  Paolo Losi
   - 4  Vincent Schut
   - 3  Alexis Metaireau
   - 3  Bryan Silverthorn
   - 3  `Andreas Müller`_
   - 2  Minwoo Jake Lee
   - 1  Emmanuelle Gouillart
   - 1  Keith Goodman
   - 1  Lucas Wiman
   - 1  `Nicolas Pinto`_
   - 1  Thouis (Ray) Jones
   - 1  Tim Sheerman-Chase


.. _changes_0_8:

Version 0.8
===========

**May 11, 2011**

scikit-learn 0.8 was released on May 2011, one month after the first
"international" `scikit-learn coding sprint
<https://github.com/scikit-learn/scikit-learn/wiki/Upcoming-events>`_ and is
marked by the inclusion of important modules: :ref:`hierarchical_clustering`,
:ref:`cross_decomposition`, :ref:`NMF`, initial support for Python 3 and by important
enhancements and bug fixes.


Changelog
---------

Several new modules where introduced during this release:

  - New :ref:`hierarchical_clustering` module by Vincent Michel,
    `Bertrand Thirion`_, `Alexandre Gramfort`_ and `Gael Varoquaux`_.

  - :ref:`kernel_pca` implementation by `Mathieu Blondel`_

  - :ref:`labeled_faces_in_the_wild` by `Olivier Grisel`_.

  - New :ref:`cross_decomposition` module by `Edouard Duchesnay`_.

  - :ref:`NMF` module `Vlad Niculae`_

  - Implementation of the :ref:`oracle_approximating_shrinkage` algorithm by
    :user:`Virgile Fritsch <VirgileFritsch>` in the :ref:`covariance` module.


Some other modules benefited from significant improvements or cleanups.


  - Initial support for Python 3: builds and imports cleanly,
    some modules are usable while others have failing tests by `Fabian Pedregosa`_.

  - :class:`decomposition.PCA` is now usable from the Pipeline object by `Olivier Grisel`_.

  - Guide :ref:`performance-howto` by `Olivier Grisel`_.

  - Fixes for memory leaks in libsvm bindings, 64-bit safer BallTree by Lars Buitinck.

  - bug and style fixing in :ref:`k_means` algorithm by Jan Schlüter.

  - Add attribute converged to Gaussian Mixture Models by Vincent Schut.

  - Implemented ``transform``, ``predict_log_proba`` in
    :class:`discriminant_analysis.LinearDiscriminantAnalysis` By `Mathieu Blondel`_.

  - Refactoring in the :ref:`svm` module and bug fixes by `Fabian Pedregosa`_,
    `Gael Varoquaux`_ and Amit Aides.

  - Refactored SGD module (removed code duplication, better variable naming),
    added interface for sample weight by `Peter Prettenhofer`_.

  - Wrapped BallTree with Cython by Thouis (Ray) Jones.

  - Added function :func:`svm.l1_min_c` by Paolo Losi.

  - Typos, doc style, etc. by `Yaroslav Halchenko`_, `Gael Varoquaux`_,
    `Olivier Grisel`_, Yann Malet, `Nicolas Pinto`_, Lars Buitinck and
    `Fabian Pedregosa`_.


People
-------

People that made this release possible preceded by number of commits:


   - 159  `Olivier Grisel`_
   - 96  `Gael Varoquaux`_
   - 96  `Vlad Niculae`_
   - 94  `Fabian Pedregosa`_
   - 36  `Alexandre Gramfort`_
   - 32  Paolo Losi
   - 31  `Edouard Duchesnay`_
   - 30  `Mathieu Blondel`_
   - 25  `Peter Prettenhofer`_
   - 22  `Nicolas Pinto`_
   - 11  :user:`Virgile Fritsch <VirgileFritsch>`
   -  7  Lars Buitinck
   -  6  Vincent Michel
   -  5  `Bertrand Thirion`_
   -  4  Thouis (Ray) Jones
   -  4  Vincent Schut
   -  3  Jan Schlüter
   -  2  Julien Miotte
   -  2  `Matthieu Perrot`_
   -  2  Yann Malet
   -  2  `Yaroslav Halchenko`_
   -  1  Amit Aides
   -  1  `Andreas Müller`_
   -  1  Feth Arezki
   -  1  Meng Xinfan


.. _changes_0_7:

Version 0.7
===========

**March 2, 2011**

scikit-learn 0.7 was released in March 2011, roughly three months
after the 0.6 release. This release is marked by the speed
improvements in existing algorithms like k-Nearest Neighbors and
K-Means algorithm and by the inclusion of an efficient algorithm for
computing the Ridge Generalized Cross Validation solution. Unlike the
preceding release, no new modules where added to this release.

Changelog
---------

  - Performance improvements for Gaussian Mixture Model sampling [Jan
    Schlüter].

  - Implementation of efficient leave-one-out cross-validated Ridge in
    :class:`linear_model.RidgeCV` [`Mathieu Blondel`_]

  - Better handling of collinearity and early stopping in
    :func:`linear_model.lars_path` [`Alexandre Gramfort`_ and `Fabian
    Pedregosa`_].

  - Fixes for liblinear ordering of labels and sign of coefficients
    [Dan Yamins, Paolo Losi, `Mathieu Blondel`_ and `Fabian Pedregosa`_].

  - Performance improvements for Nearest Neighbors algorithm in
    high-dimensional spaces [`Fabian Pedregosa`_].

  - Performance improvements for :class:`cluster.KMeans` [`Gael
    Varoquaux`_ and `James Bergstra`_].

  - Sanity checks for SVM-based classes [`Mathieu Blondel`_].

  - Refactoring of :class:`neighbors.NeighborsClassifier` and
    :func:`neighbors.kneighbors_graph`: added different algorithms for
    the k-Nearest Neighbor Search and implemented a more stable
    algorithm for finding barycenter weights. Also added some
    developer documentation for this module, see
    `notes_neighbors
    <https://github.com/scikit-learn/scikit-learn/wiki/Neighbors-working-notes>`_ for more information [`Fabian Pedregosa`_].

  - Documentation improvements: Added :class:`pca.RandomizedPCA` and
    :class:`linear_model.LogisticRegression` to the class
    reference. Also added references of matrices used for clustering
    and other fixes [`Gael Varoquaux`_, `Fabian Pedregosa`_, `Mathieu
    Blondel`_, `Olivier Grisel`_, Virgile Fritsch , Emmanuelle
    Gouillart]

  - Binded decision_function in classes that make use of liblinear_,
    dense and sparse variants, like :class:`svm.LinearSVC` or
    :class:`linear_model.LogisticRegression` [`Fabian Pedregosa`_].

  - Performance and API improvements to
    :func:`metrics.euclidean_distances` and to
    :class:`pca.RandomizedPCA` [`James Bergstra`_].

  - Fix compilation issues under NetBSD [Kamel Ibn Hassen Derouiche]

  - Allow input sequences of different lengths in :class:`hmm.GaussianHMM`
    [`Ron Weiss`_].

  - Fix bug in affinity propagation caused by incorrect indexing [Xinfan Meng]


People
------

People that made this release possible preceded by number of commits:

    - 85  `Fabian Pedregosa`_
    - 67  `Mathieu Blondel`_
    - 20  `Alexandre Gramfort`_
    - 19  `James Bergstra`_
    - 14  Dan Yamins
    - 13  `Olivier Grisel`_
    - 12  `Gael Varoquaux`_
    - 4  `Edouard Duchesnay`_
    - 4  `Ron Weiss`_
    - 2  Satrajit Ghosh
    - 2  Vincent Dubourg
    - 1  Emmanuelle Gouillart
    - 1  Kamel Ibn Hassen Derouiche
    - 1  Paolo Losi
    - 1  VirgileFritsch
    - 1  `Yaroslav Halchenko`_
    - 1  Xinfan Meng


.. _changes_0_6:

Version 0.6
===========

**December 21, 2010**

scikit-learn 0.6 was released on December 2010. It is marked by the
inclusion of several new modules and a general renaming of old
ones. It is also marked by the inclusion of new example, including
applications to real-world datasets.


Changelog
---------

  - New `stochastic gradient
    <http://scikit-learn.org/stable/modules/sgd.html>`_ descent
    module by Peter Prettenhofer. The module comes with complete
    documentation and examples.

  - Improved svm module: memory consumption has been reduced by 50%,
    heuristic to automatically set class weights, possibility to
    assign weights to samples (see
    :ref:`sphx_glr_auto_examples_svm_plot_weighted_samples.py` for an example).

  - New :ref:`gaussian_process` module by Vincent Dubourg. This module
    also has great documentation and some very neat examples. See
    example_gaussian_process_plot_gp_regression.py or
    example_gaussian_process_plot_gp_probabilistic_classification_after_regression.py
    for a taste of what can be done.

  - It is now possible to use liblinear’s Multi-class SVC (option
    multi_class in :class:`svm.LinearSVC`)

  - New features and performance improvements of text feature
    extraction.

  - Improved sparse matrix support, both in main classes
    (:class:`grid_search.GridSearchCV`) as in modules
    sklearn.svm.sparse and sklearn.linear_model.sparse.

  - Lots of cool new examples and a new section that uses real-world
    datasets was created. These include:
    :ref:`sphx_glr_auto_examples_applications_face_recognition.py`,
    :ref:`sphx_glr_auto_examples_applications_plot_species_distribution_modeling.py`,
    :ref:`sphx_glr_auto_examples_applications_svm_gui.py`,
    :ref:`sphx_glr_auto_examples_applications_wikipedia_principal_eigenvector.py` and
    others.

  - Faster :ref:`least_angle_regression` algorithm. It is now 2x
    faster than the R version on worst case and up to 10x times faster
    on some cases.

  - Faster coordinate descent algorithm. In particular, the full path
    version of lasso (:func:`linear_model.lasso_path`) is more than
    200x times faster than before.

  - It is now possible to get probability estimates from a
    :class:`linear_model.LogisticRegression` model.

  - module renaming: the glm module has been renamed to linear_model,
    the gmm module has been included into the more general mixture
    model and the sgd module has been included in linear_model.

  - Lots of bug fixes and documentation improvements.


People
------

People that made this release possible preceded by number of commits:

   * 207  `Olivier Grisel`_

   * 167 `Fabian Pedregosa`_

   * 97 `Peter Prettenhofer`_

   * 68 `Alexandre Gramfort`_

   * 59  `Mathieu Blondel`_

   * 55  `Gael Varoquaux`_

   * 33  Vincent Dubourg

   * 21  `Ron Weiss`_

   * 9  Bertrand Thirion

   * 3  `Alexandre Passos`_

   * 3  Anne-Laure Fouque

   * 2  Ronan Amicel

   * 1 `Christian Osendorfer`_



.. _changes_0_5:


Version 0.5
===========

**October 11, 2010**

Changelog
---------

New classes
-----------

    - Support for sparse matrices in some classifiers of modules
      ``svm`` and ``linear_model`` (see :class:`svm.sparse.SVC`,
      :class:`svm.sparse.SVR`, :class:`svm.sparse.LinearSVC`,
      :class:`linear_model.sparse.Lasso`, :class:`linear_model.sparse.ElasticNet`)

    - New :class:`pipeline.Pipeline` object to compose different estimators.

    - Recursive Feature Elimination routines in module
      :ref:`feature_selection`.

    - Addition of various classes capable of cross validation in the
      linear_model module (:class:`linear_model.LassoCV`, :class:`linear_model.ElasticNetCV`,
      etc.).

    - New, more efficient LARS algorithm implementation. The Lasso
      variant of the algorithm is also implemented. See
      :class:`linear_model.lars_path`, :class:`linear_model.Lars` and
      :class:`linear_model.LassoLars`.

    - New Hidden Markov Models module (see classes
      :class:`hmm.GaussianHMM`, :class:`hmm.MultinomialHMM`,
      :class:`hmm.GMMHMM`)

    - New module feature_extraction (see :ref:`class reference
      <feature_extraction_ref>`)

    - New FastICA algorithm in module sklearn.fastica


Documentation
-------------

    - Improved documentation for many modules, now separating
      narrative documentation from the class reference. As an example,
      see `documentation for the SVM module
      <http://scikit-learn.org/stable/modules/svm.html>`_ and the
      complete `class reference
      <http://scikit-learn.org/stable/modules/classes.html>`_.

Fixes
-----

    - API changes: adhere variable names to PEP-8, give more
      meaningful names.

    - Fixes for svm module to run on a shared memory context
      (multiprocessing).

    - It is again possible to generate latex (and thus PDF) from the
      sphinx docs.

Examples
--------

    - new examples using some of the mlcomp datasets:
      ``sphx_glr_auto_examples_mlcomp_sparse_document_classification.py`` (since removed) and
      :ref:`sphx_glr_auto_examples_text_document_classification_20newsgroups.py`

    - Many more examples. `See here
      <http://scikit-learn.org/stable/auto_examples/index.html>`_
      the full list of examples.


External dependencies
---------------------

    - Joblib is now a dependency of this package, although it is
      shipped with (sklearn.externals.joblib).

Removed modules
---------------

    - Module ann (Artificial Neural Networks) has been removed from
      the distribution. Users wanting this sort of algorithms should
      take a look into pybrain.

Misc
----

    - New sphinx theme for the web page.


Authors
-------

The following is a list of authors for this release, preceded by
number of commits:

     * 262  Fabian Pedregosa
     * 240  Gael Varoquaux
     * 149  Alexandre Gramfort
     * 116  Olivier Grisel
     *  40  Vincent Michel
     *  38  Ron Weiss
     *  23  Matthieu Perrot
     *  10  Bertrand Thirion
     *   7  Yaroslav Halchenko
     *   9  VirgileFritsch
     *   6  Edouard Duchesnay
     *   4  Mathieu Blondel
     *   1  Ariel Rokem
     *   1  Matthieu Brucher

Version 0.4
===========

**August 26, 2010**

Changelog
---------

Major changes in this release include:

    - Coordinate Descent algorithm (Lasso, ElasticNet) refactoring &
      speed improvements (roughly 100x times faster).

    - Coordinate Descent Refactoring (and bug fixing) for consistency
      with R's package GLMNET.

    - New metrics module.

    - New GMM module contributed by Ron Weiss.

    - Implementation of the LARS algorithm (without Lasso variant for now).

    - feature_selection module redesign.

    - Migration to GIT as version control system.

    - Removal of obsolete attrselect module.

    - Rename of private compiled extensions (added underscore).

    - Removal of legacy unmaintained code.

    - Documentation improvements (both docstring and rst).

    - Improvement of the build system to (optionally) link with MKL.
      Also, provide a lite BLAS implementation in case no system-wide BLAS is
      found.

    - Lots of new examples.

    - Many, many bug fixes ...


Authors
-------

The committer list for this release is the following (preceded by number
of commits):

    * 143  Fabian Pedregosa
    * 35  Alexandre Gramfort
    * 34  Olivier Grisel
    * 11  Gael Varoquaux
    *  5  Yaroslav Halchenko
    *  2  Vincent Michel
    *  1  Chris Filo Gorgolewski


Earlier versions
================

Earlier versions included contributions by Fred Mailhot, David Cooke,
David Huard, Dave Morrill, Ed Schofield, Travis Oliphant, Pearu Peterson.

.. _Olivier Grisel: https://twitter.com/ogrisel

.. _Gael Varoquaux: http://gael-varoquaux.info

.. _Alexandre Gramfort: http://alexandre.gramfort.net

.. _Fabian Pedregosa: http://fa.bianp.net

.. _Mathieu Blondel: http://www.mblondel.org

.. _James Bergstra: http://www-etud.iro.umontreal.ca/~bergstrj/

.. _liblinear: http://www.csie.ntu.edu.tw/~cjlin/liblinear/

.. _Yaroslav Halchenko: http://www.onerussian.com/

.. _Vlad Niculae: http://vene.ro

.. _Edouard Duchesnay: https://sites.google.com/site/duchesnay/home

.. _Peter Prettenhofer: https://sites.google.com/site/peterprettenhofer/

.. _Alexandre Passos: http://atpassos.me

.. _Nicolas Pinto: https://twitter.com/npinto

.. _Bertrand Thirion: https://team.inria.fr/parietal/bertrand-thirions-page

.. _Andreas Müller: http://peekaboo-vision.blogspot.com

.. _Matthieu Perrot: http://brainvisa.info/biblio/lnao/en/Author/PERROT-M.html

.. _Jake Vanderplas: http://staff.washington.edu/jakevdp/

.. _Gilles Louppe: http://www.montefiore.ulg.ac.be/~glouppe/

.. _INRIA: http://www.inria.fr

.. _Parietal Team: http://parietal.saclay.inria.fr/

.. _David Warde-Farley: http://www-etud.iro.umontreal.ca/~wardefar/

.. _Brian Holt: http://personal.ee.surrey.ac.uk/Personal/B.Holt

.. _Satrajit Ghosh: http://www.mit.edu/~satra/

.. _Robert Layton: https://twitter.com/robertlayton

.. _Scott White: https://twitter.com/scottblanc

.. _David Marek: http://www.davidmarek.cz/

.. _Christian Osendorfer: https://osdf.github.io

.. _Arnaud Joly: http://www.ajoly.org

.. _Rob Zinkov: http://zinkov.com

.. _Joel Nothman: http://joelnothman.com

.. _Nicolas Trésegnie : http://nicolastr.com/

.. _Kemal Eren: http://www.kemaleren.com

.. _Yann Dauphin: http://ynd.github.io/

.. _Yannick Schwartz: https://team.inria.fr/parietal/schwarty/

.. _Mikhail Korobov: http://kmike.ru/pages/about/

.. _Kyle Kastner: http://kastnerkyle.github.io

.. _Daniel Nouri: http://danielnouri.org

.. _Manoj Kumar: https://manojbits.wordpress.com

.. _Luis Pedro Coelho: http://luispedro.org

.. _Fares Hedyati: http://www.eecs.berkeley.edu/~fareshed

.. _Antony Lee: https://www.ocf.berkeley.edu/~antonyl/

.. _Martin Billinger: http://tnsre.embs.org/author/martinbillinger

.. _Matteo Visconti di Oleggio Castello: http://www.mvdoc.me

.. _Trevor Stephens: http://trevorstephens.com/

.. _Jan Hendrik Metzen: https://jmetzen.github.io/

.. _Will Dawson: http://www.dawsonresearch.com

.. _Andrew Tulloch: http://tullo.ch/

.. _Hanna Wallach: http://dirichlet.net/

.. _Yan Yi: http://seowyanyi.org

.. _Hervé Bredin: http://herve.niderb.fr/

.. _Eric Martin: http://www.ericmart.in

.. _Nicolas Goix: https://webperso.telecom-paristech.fr/front/frontoffice.php?SP_ID=241

.. _Sebastian Raschka: http://sebastianraschka.com

.. _Brian McFee: https://bmcfee.github.io

.. _Valentin Stolbunov: http://www.vstolbunov.com

.. _Jaques Grobler: https://github.com/jaquesgrobler

.. _Lars Buitinck: https://github.com/larsmans

.. _Loic Esteve: https://github.com/lesteve

.. _Noel Dawe: https://github.com/ndawe

.. _Raghav RV: https://github.com/raghavrv

.. _Tom Dupre la Tour: https://github.com/TomDLT

.. _Nelle Varoquaux: https://github.com/nellev

.. _Bing Tian Dai: https://github.com/btdai

.. _Dylan Werner-Meier: https://github.com/unautre

.. _Alyssa Batula: https://github.com/abatula

.. _Srivatsan Ramesh: https://github.com/srivatsan-ramesh

.. _Ron Weiss: http://www.ee.columbia.edu/~ronw

.. _Narine Kokhlikyan: https://github.com/NarineK

.. _Peng Meng: https://github.com/mpjlu