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How can Keras be used to evaluate the model using Python?

Tensorflow is a machine learning framework that is provided by Google. It is an open−source framework used in conjunction with Python to implement algorithms, deep learning applications and much more. It is used in research and for production purposes.

Keras was developed as a part of research for the project ONEIROS (Open ended Neuro−Electronic Intelligent Robot Operating System). Keras is a deep learning API, which is written in Python. It is a high−level API that has a productive interface that helps solve machine learning problems. It runs on top of Tensorflow framework. It was built to help experiment in a quick manner.

It provides essential abstractions and building blocks that are essential in developing and encapsulating machine learning solutions. It is highly scalable, and comes with cross platform abilities. This means Keras can be run on TPU or clusters of GPUs. Keras models can also be exported to run in a web browser or a mobile phone as well.

Keras is already present within the Tensorflow package. It can be accessed using the below line of code −

import tensorflow
from tensorflow import keras

We are using the Google Colaboratory to run the below code. Google Colab or Colaboratory helps run Python code over the browser and requires zero configuration and free access to GPUs (Graphical Processing Units). Colaboratory has been built on top of Jupyter Notebook. Following is the code −

Example

print("An instance of the model is created")
model = create_model()

print("The model is being evaluated")
loss, acc = model.evaluate(test_images, test_labels, verbose=2)
print("This is an untrained model, with accuracy: {:5.3f}%".format(100 * acc))

Code credit − https://www.tensorflow.org/tutorials/keras/save_and_load

Output

An Instance of the model is created 
The Model is being evaluated 32/32 -0s - loss: - spare_categories_accurancy: 0.0930 
This is an untrained model, with accuracy: 9.300%

Explanation

  • An instance of the model is created.

  • This is a new, untrained model which is evaluated on the test set.

  • The ‘evaluate’ method is used to check how well the model performs on new data.

  • In addition, the loss when the model is being trained and the accuracy of the model are both determined.

  • The loss and accuracy are printed on the console.