losses.py

# The MIT-Zero License

# Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.

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# of this software and associated documentation files (the "Software"), to deal
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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import keras
from keras import backend as K


class Loss():
    @staticmethod
    def built_in_softmax_kl_loss(target, output):
        '''
        Custom Loss Function
        :param target: ground truth values
        :param output: predicted values
        :return kullback_leibler_divergence loss
        '''
        target = K.flatten(target)
        output = K.flatten(output)
        target = target / K.sum(target)
        output = K.softmax(output)
        return keras.losses.kullback_leibler_divergence(target, output)