0.19/index.html



<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    
  
    <title>scikit-learn: machine learning in Python &#8212; scikit-learn 0.19.2 documentation</title>
  <!-- htmltitle is before nature.css - we use this hack to load bootstrap first -->
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <link rel="stylesheet" href="_static/css/bootstrap.min.css" media="screen" />
  <link rel="stylesheet" href="_static/css/bootstrap-responsive.css"/>

    
    <link rel="stylesheet" href="_static/nature.css" type="text/css" />
    <link rel="stylesheet" href="_static/pygments.css" type="text/css" />
    <link rel="stylesheet" href="_static/gallery.css" type="text/css" />
    
    <script type="text/javascript">
      var DOCUMENTATION_OPTIONS = {
        URL_ROOT:    './',
        VERSION:     '0.19.2',
        COLLAPSE_INDEX: false,
        FILE_SUFFIX: '.html',
        HAS_SOURCE:  true,
        SOURCELINK_SUFFIX: '.txt'
      };
    </script>
    <script type="text/javascript" src="_static/jquery.js"></script>
    <script type="text/javascript" src="_static/underscore.js"></script>
    <script type="text/javascript" src="_static/doctools.js"></script>
    <script type="text/javascript" src="_static/js/copybutton.js"></script>
    <link rel="shortcut icon" href="_static/favicon.ico"/>
    <link rel="author" title="About these documents" href="about.html" />
    <link rel="search" title="Search" href="search.html" />
    <link rel="next" title="scikit-learn" href="preface.html" />
  
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <script src="_static/js/bootstrap.min.js" type="text/javascript"></script>
  <script>
     VERSION_SUBDIR = (function(groups) {
         return groups ? groups[1] : null;
     })(location.href.match(/^https?:\/\/scikit-learn.org\/([^\/]+)/));
  </script>
  <link rel="canonical" href="https://scikit-learn.org/stable/index.html" />

  <script type="text/javascript">
    $("div.buttonNext, div.buttonPrevious").hover(
       function () {
           $(this).css('background-color', '#FF9C34');
       },
       function () {
           $(this).css('background-color', '#A7D6E2');
       }
    );
    function showMenu() {
      var topNav = document.getElementById("scikit-navbar");
      if (topNav.className === "navbar") {
          topNav.className += " responsive";
      } else {
          topNav.className = "navbar";
      }
    };
  </script>

  </head>
  <body>

<div class="header-wrapper">
    <div class="header">
        <p class="logo"><a href="#">
            <img src="_static/scikit-learn-logo-small.png" alt="Logo"/>
        </a>
        </p><div class="navbar" id="scikit-navbar">
            <ul>
                <li><a href="#">Home</a></li>
                <li><a href="install.html">Installation</a></li>
                <li class="btn-li"><div class="btn-group">
              <a href="documentation.html">Documentation</a>
              <a class="btn dropdown-toggle" data-toggle="dropdown">
                 <span class="caret"></span>
              </a>
              <ul class="dropdown-menu">
            <li class="link-title">Scikit-learn <script>document.write(DOCUMENTATION_OPTIONS.VERSION + (VERSION_SUBDIR ? " (" + VERSION_SUBDIR + ")" : ""));</script></li>
            <li><a href="tutorial/index.html">Tutorials</a></li>
            <li><a href="user_guide.html">User guide</a></li>
            <li><a href="modules/classes.html">API</a></li>
            <li><a href="faq.html">FAQ</a></li>
            <li><a href="developers/contributing.html">Contributing</a></li>
            <li class="divider"></li>
                <script>if (VERSION_SUBDIR != "stable") document.write('<li><a href="http://scikit-learn.org/stable/documentation.html">Stable version</a></li>')</script>
                <script>if (VERSION_SUBDIR != "dev") document.write('<li><a href="http://scikit-learn.org/dev/documentation.html">Development version</a></li>')</script>
                <li><a href="http://scikit-learn.org/dev/versions.html">All available versions</a></li>
                <li><a href="_downloads/scikit-learn-docs.pdf">PDF documentation</a></li>
              </ul>
            </div>
        </li>
            <li><a href="auto_examples/index.html">Examples</a></li>
            </ul>
            <a href="javascript:void(0);" onclick="showMenu()">
                <div class="nav-icon">
                    <div class="hamburger-line"></div>
                    <div class="hamburger-line"></div>
                    <div class="hamburger-line"></div>
                </div>
            </a>
            <div class="search_form">
                <div class="gcse-search" id="cse" style="width: 100%;"></div>
            </div>
        </div> <!-- end navbar --></div>
</div>
<!-- Banner -->
<div class="container banner-container">
  <div class="row-fluid banner-inner">
    <div class="hidden-phone">
      <div class="span6">
	<div class="row-fluid">
          <div class="offset2 span8"><div id="index_carousel_tn" class="thumbnail">
	      <div id="examples_carousel" class="carousel slide" data-interval="false">
		<ol id="scikit_learn_index_indicators" class="carousel-indicators">
		  <li data-target="#examples_carousel" data-slide-to="0" class="active"></li>
		  <li data-target="#examples_carousel" data-slide-to="1"></li>
		  <li data-target="#examples_carousel" data-slide-to="2"></li>
		  <li data-target="#examples_carousel" data-slide-to="3"></li>
		  <li data-target="#examples_carousel" data-slide-to="4"></li>
		  <li data-target="#examples_carousel" data-slide-to="5"></li>
		  <li data-target="#examples_carousel" data-slide-to="6"></li>
		  <li data-target="#examples_carousel" data-slide-to="7"></li>
		  <li data-target="#examples_carousel" data-slide-to="8"></li>
		  <li data-target="#examples_carousel" data-slide-to="9"></li>
		</ol>
		<!-- Carousel items -->
		<div class="carousel-inner">
		  <div class="active item">
		    <a href="auto_examples/classification/plot_classifier_comparison.html">
		      <div class="crop-wrapper" style="width: 380px; height: 190px; overflow: hidden">
			<img src="_images/sphx_glr_plot_classifier_comparison_001_carousel.png"
			     style="max-height: 200px; max-width: 629px; margin-left: -21px;"></div></a>
		  </div>
		  <div class="item">
		    <a href="auto_examples/covariance/plot_outlier_detection.html">
		      <img src="_images/sphx_glr_plot_outlier_detection_003_carousel.png"></a>
		  </div>
		  <div class="item">
		    <a href="auto_examples/neighbors/plot_species_kde.html">
		      <img src="_images/sphx_glr_plot_species_kde_thumb.png"></a>
		  </div>
		  <div class="item">
		    <a href="auto_examples/linear_model/plot_lasso_lars.html">
		      <img src="_images/sphx_glr_plot_lasso_lars_thumb.png"></a>
		  </div>
		  <div class="item">
		    <a href="auto_examples/cluster/plot_cluster_comparison.html">
		      <img src="_images/sphx_glr_plot_cluster_comparison_thumb.png"></a>
		  </div>
		  <div class="item">
		    <a href="auto_examples/ensemble/plot_adaboost_twoclass.html">
		      <img src="_images/sphx_glr_plot_adaboost_twoclass_001_carousel.png"></a>
		  </div>
		  <div class="item">
		    <a href="auto_examples/gaussian_process/plot_gpr_co2.html">
		      <img src="_images/sphx_glr_plot_gpr_co2_001_carousel.png"></a>
		  </div>
		  <div class="item">
		    <a href="auto_examples/manifold/plot_compare_methods.html">
		      <img src="_images/sphx_glr_plot_compare_methods_001_carousel.png"></a>
		  </div>
		  <div class="item">
		    <a href="auto_examples/mixture/plot_gmm_pdf.html">
		      <img src="_images/sphx_glr_plot_gmm_pdf_thumb.png"></a>
		  </div>
		  <div class="item">
		    <a href="auto_examples/cluster/plot_face_ward_segmentation.html">
		      <img src="_images/sphx_glr_plot_face_ward_segmentation_thumb.png"></a>
		  </div>
		</div>
		<!-- Carousel nav -->
		<a class="carousel-control left" href="#examples_carousel" data-slide="prev">&lsaquo;</a>
		<a class="carousel-control right" href="#examples_carousel" data-slide="next">&rsaquo;</a>
	      </div>
	  </div></div>
	</div>
      </div>
    </div>
    <div id="intro_to_sklearn_p" class="span6">
      <h1>scikit-learn</h1>
      <h2>Machine Learning in Python</h2>
      <ul>
        <li>Simple and efficient tools for data mining and data analysis</li>
        <li>Accessible to everybody, and reusable in various contexts</li>
        <li>Built on NumPy, SciPy, and matplotlib</li>
        <li>Open source, commercially usable - BSD license</li>
      </ul>
    </div>
  </div>
</div>


<!-- GitHub "fork me" ribbon -->
<a href="https://github.com/scikit-learn/scikit-learn">
  <img class="fork-me"
       style="position: absolute; top: 0; right: 0; border: 0;"
       src="_static/img/forkme.png"
       alt="Fork me on GitHub" />
</a>

<div class="content-wrapper">


      <div class="content">
            
      <div class="documentwrapper">
        <div class="bodywrapper">
          <div class="body" role="main">
            
  <!-- Block section -->
<div class="container-index">
<div class="container index-upper">
<div class="row-fluid">

<!-- Classification -->
<div class="span4 box">
<h2 ><p><a class="reference internal" href="supervised_learning.html#supervised-learning"><span class="std std-ref">Classification</span></a></p>
</h2>
<blockquote>
<p>Identifying to which category an object belongs to.</p>
<div class="box-links">
<strong>Applications</strong>: Spam detection, Image recognition.</br>
<strong>Algorithms</strong>:&nbsp;<p><a class="reference internal" href="modules/svm.html#svm"><span class="std std-ref">SVM</span></a>, <a class="reference internal" href="modules/neighbors.html#classification"><span class="std std-ref">nearest neighbors</span></a>, <a class="reference internal" href="modules/ensemble.html#forest"><span class="std std-ref">random forest</span></a>, …</p>
<small class="float-right box-example-links"><p><a class="reference internal" href="auto_examples/index.html#general-examples"><span class="std std-ref">Examples</span></a></p>
</small>
</div>
</blockquote>
</div>

<!-- Regression -->
<div class="span4 box">
<h2><p><a class="reference internal" href="supervised_learning.html#supervised-learning"><span class="std std-ref">Regression</span></a></p>
</h2>
<blockquote>
<p>Predicting a continuous-valued attribute associated with an object.</p>
<div class="box-links">
<strong>Applications</strong>: Drug response, Stock prices.</br>
<strong>Algorithms</strong>:&nbsp;<p><a class="reference internal" href="modules/svm.html#svm"><span class="std std-ref">SVR</span></a>, <a class="reference internal" href="modules/linear_model.html#ridge-regression"><span class="std std-ref">ridge regression</span></a>, <a class="reference internal" href="modules/linear_model.html#lasso"><span class="std std-ref">Lasso</span></a>, …</p>
<small class="float-right box-example-links"><p><a class="reference internal" href="auto_examples/index.html#general-examples"><span class="std std-ref">Examples</span></a></p>
</small>
</div>
</blockquote>
</div>

<!-- Clustering -->
<div class="span4 box">
<h2><p><a class="reference internal" href="modules/clustering.html#clustering"><span class="std std-ref">Clustering</span></a></p>
</h2>
<blockquote>
<p>Automatic grouping of similar objects into sets.</p>
<div class="box-links">
<strong>Applications</strong>: Customer segmentation, Grouping experiment outcomes</br>
<strong>Algorithms</strong>:&nbsp;<p><a class="reference internal" href="modules/clustering.html#k-means"><span class="std std-ref">k-Means</span></a>, <a class="reference internal" href="modules/clustering.html#spectral-clustering"><span class="std std-ref">spectral clustering</span></a>, <a class="reference internal" href="modules/clustering.html#mean-shift"><span class="std std-ref">mean-shift</span></a>, …</p>
<small class="float-right example-links"><p><a class="reference internal" href="auto_examples/index.html#cluster-examples"><span class="std std-ref">Examples</span></a></p>
</small>
</div>
</blockquote>
</div>

<!-- row -->
</div>
<div class="row-fluid">

<!-- Dimension reduction -->
<div class="span4 box">
<h2><p><a class="reference internal" href="modules/decomposition.html#decompositions"><span class="std std-ref">Dimensionality reduction</span></a></p>
</h2>
<blockquote>
<p>Reducing the number of random variables to consider.</p>
<div class="box-links">
<strong>Applications</strong>: Visualization, Increased efficiency</br>
<strong>Algorithms</strong>:&nbsp;<p><a class="reference internal" href="modules/decomposition.html#pca"><span class="std std-ref">PCA</span></a>, <a class="reference internal" href="modules/feature_selection.html#feature-selection"><span class="std std-ref">feature selection</span></a>, <a class="reference internal" href="modules/decomposition.html#nmf"><span class="std std-ref">non-negative matrix factorization</span></a>.</p>
<small class="float-right example-links"><p><a class="reference internal" href="auto_examples/index.html#decomposition-examples"><span class="std std-ref">Examples</span></a></p>
</small>
</div>
</blockquote>
</div>

<!-- Model selection -->
<div class="span4 box">
<h2><p><a class="reference internal" href="model_selection.html#model-selection"><span class="std std-ref">Model selection</span></a></p>
</h2>
<blockquote>
<p>Comparing, validating and choosing parameters and models.</p>
<div class="box-links">
<strong>Goal</strong>: Improved accuracy via parameter tuning</br>
<strong>Modules</strong>:&nbsp;<p><a class="reference internal" href="modules/grid_search.html#grid-search"><span class="std std-ref">grid search</span></a>, <a class="reference internal" href="modules/cross_validation.html#cross-validation"><span class="std std-ref">cross validation</span></a>, <a class="reference internal" href="modules/model_evaluation.html#model-evaluation"><span class="std std-ref">metrics</span></a>.</p>
<small class="float-right example-links"><p><a class="reference internal" href="auto_examples/index.html#general-examples"><span class="std std-ref">Examples</span></a></p>
</small>
</div>
</blockquote>
</div>


<!-- Preprocessing -->
<div class="span4 box">
<h2><p><a class="reference internal" href="modules/preprocessing.html#preprocessing"><span class="std std-ref">Preprocessing</span></a></p>
</h2>
<blockquote>
<p>Feature extraction and normalization.</p>
<div class="box-links">
<strong>Application</strong>: Transforming input data such as text for use with machine learning algorithms.</br>
<strong>Modules</strong>:&nbsp;<p><a class="reference internal" href="modules/preprocessing.html#preprocessing"><span class="std std-ref">preprocessing</span></a>, <a class="reference internal" href="modules/feature_extraction.html#feature-extraction"><span class="std std-ref">feature extraction</span></a>.</p>
<span class="example-links">
<small class="float-right example-links"><p><a class="reference internal" href="auto_examples/index.html#general-examples"><span class="std std-ref">Examples</span></a></p>
</small>
</div>
</blockquote>
</div>

<!-- row -->
</div>
</div> <!-- container -->


<div class="container index-lower">
    <div class="row-fluid">
        <!-- News -->
        <div class="span4">
            <h4>News</h4>
            <ul>
            <li><em>On-going development:</em>
            <a href="/dev/whats_new.html"><em>What's new</em> (Changelog)</a>
            </li>
            <li><em>July 2018.</em> scikit-learn 0.19.2 is available for download (<a href="whats_new.html#version-0-19-2">Changelog</a>).
            </li>
            <li><em>October 2017.</em> scikit-learn 0.19.1 is available for download (<a href="whats_new.html#version-0-19-1">Changelog</a>).
            </li>
            <li><em>July 2017.</em> scikit-learn 0.19.0 is available for download (<a href="whats_new.html#version-0-19">Changelog</a>).
            </li>
            <li><em>June 2017.</em> scikit-learn 0.18.2 is available for download (<a href="whats_new.html#version-0-18-2">Changelog</a>).
            </li>
            <li><em>September 2016.</em> scikit-learn 0.18.0 is available for download (<a href="whats_new.html#version-0-18">Changelog</a>).
            </li>
            <li><em>November 2015.</em> scikit-learn 0.17.0 is available for download (<a href="whats_new.html#version-0-17">Changelog</a>).
            </li>
            <li><em>March 2015.</em> scikit-learn 0.16.0 is available for download (<a href="whats_new.html#version-0-16">Changelog</a>).
            </li>
            </ul>
        </div>

        <!-- Community -->
        <div class="span4">
            <h4>Community</h4>
            <ul>
            <li><em>About us</em> See <a href="about.html#people">authors</a> and <a href="developers/contributing.html">contributing</a></li>
            <li><em>More Machine Learning</em> Find <a href="related_projects.html">related projects</a></li>
            <li><em>Questions?</em> See <a href="faq.html">FAQ</a> and <a href="http://stackoverflow.com/questions/tagged/scikit-learn">stackoverflow</a></li>
            <li><em>Mailing list:</em> <a href="https://mail.python.org/mailman/listinfo/scikit-learn">scikit-learn@python.org</a></li>
            <li><em>IRC:</em> #scikit-learn @ <a href="http://webchat.freenode.net/">freenode</a></li>
            </ul>

            <form target="_top" id="paypal-form" method="post" action="https://www.paypal.com/cgi-bin/webscr">
                <input type="hidden" value="_s-xclick" name="cmd">
                <input type="hidden" value="74EYUMF3FTSW8" name="hosted_button_id">
            </form>

            <a class="btn btn-warning btn-big" onclick="document.getElementById('paypal-form').submit(); return false;">Help us, <strong>donate!</strong></a>
            <a class="btn btn-warning btn-big cite-us" href="./about.html#citing-scikit-learn"><strong>Cite us!</strong></a>

            <small style="display: block; margin-top: 10px"><a href="about.html#funding">Read more about donations</a></small>
        </div>

        <!-- who using -->
        <div class="span4">
            <h4>Who uses scikit-learn?</h4>

            <div id="testimonials_carousel" class="carousel slide">
                <div class="carousel-inner">
                    <div class="active item">
                      <img src="_images/inria.png" class="thumbnail" />
                      <p>
                      <em>"We use scikit-learn to support leading-edge basic research [...]"</em>
                      </p>
                    </div>
                    <div class="item">
                      <img src="_images/spotify.png" class="thumbnail" />
                      <p>
                      <em>"I think it's the most well-designed ML package I've seen so far."</em>
                      </p>
                    </div>
                    <div class="item">
                      <img src="_images/change-logo.png" class="thumbnail" />
                      <p>
                      <em>"scikit-learn's ease-of-use, performance and overall variety of algorithms implemented has proved invaluable [...]."</em>
                      </p>
                    </div>
                    <div class="item">
                      <img src="_images/evernote.png" class="thumbnail" />
                      <p>
                      <em>"For these tasks, we relied on the excellent scikit-learn package for Python."</em>
                      </p>
                    </div>
                    <div class="item">
                      <img src="_images/telecomparistech.jpg"
                           class="thumbnail" />
                      <p>
                      <em>"The great benefit of scikit-learn is its fast learning curve [...]"</em>
                      </p>
                    </div>
                    <div class="item">
                      <img src="_images/aweber.png" class="thumbnail" />
                      <p>
                      <em>"It allows us to do AWesome stuff we would not otherwise accomplish"</em>
                      </p>
                    </div>
                    <div class="item">
                      <img src="_images/yhat.png" class="thumbnail" />
                      <p>
                      <em>"scikit-learn makes doing advanced analysis in Python accessible to anyone."</em>
                      </p>
                    </div>
                </div>
            </div>
            <p align="right">
            <small class="example-link">
            <a href="testimonials/testimonials.html">More testimonials</a>
            </small>
            </p>
        </div>

    </div>
</div>

<!--Bottom of index page contributions logos-->
<div class="container index-upper" >
<div class="row-fluid">
  <div class="footer">
      <div class="span3">
        Funding provided by INRIA and others.
      </div>
      <div class="span6">
         <a class="reference internal" href="about.html#funding" style="text-decoration: none; white-space: nowrap" >
               <img id="index-funding-logo-big" src="_static/img/inria-small.png" title="INRIA">
           <img id="index-funding-logo-small" src="_static/img/google.png" title="Google">
           <!--Due to Télécom ParisTech's logo text being smaller, a style has been added to improve readability-->
           <img id="index-funding-logo-small" src="_static/img/telecom.png" title="Télécom ParisTech" style="max-height: 36px">
           <img id="index-funding-logo-small" src="_static/img/FNRS-logo.png" title="FNRS">
           <img id="index-funding-logo-small" src="_static/img/sloan_logo.jpg" title="Alfred P. Sloan Foundation" style="max-height: 36px">
           <img id="index-funding-logo-small" src="_static/img/columbia.png" title="Columbia University" style="max-height: 36px;">
           <img id="index-funding-logo-small" src="_static/img/sydney-stacked.jpeg" title="The University of Sydney" style="max-height: 36px;">
         </a>
     </div>
     <div class="span3">
        <a class="reference internal" href="about.html#funding">
           More information on our contributors
        </a>
     </div>
  </div>
</div>
  </div>
</div>


<script>
  $('#testimonials_carousel').carousel()
</script><div class="toctree-wrapper compound">
</div>


          </div>
        </div>
      </div>
        <div class="clearer"></div>
      </div>
    </div>

    <div class="footer">
    </div>
     </div>

    
    <script type="text/javascript">
      var _gaq = _gaq || [];
      _gaq.push(['_setAccount', 'UA-22606712-2']);
      _gaq.push(['_trackPageview']);

      (function() {
        var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;
        ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';
        var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);
      })();
    </script>
    
    <script>
      (function() {
        var cx = '016639176250731907682:tjtqbvtvij0';
        var gcse = document.createElement('script'); gcse.type = 'text/javascript'; gcse.async = true;
        gcse.src = 'https://cse.google.com/cse.js?cx=' + cx;
        var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(gcse, s);
      })();
    </script>
    <script src="https://scikit-learn.org/versionwarning.js"></script>
  </body>
</html>