Keras

The Keras backend implements the .fit() method with the following Keras-specific extensions:

• validation_data= can refer to a tuple of (testX, testY) dataset names instead of actual data values, similar to X, Y. This will load the validation dataset before model.fit().

• Metadata.attributes.history stores the history.history object, which is a dictionary of all metrics with one entry per epoch as the return value of Keras’s model.fit() method.