ISSN : 1738-6764
Training neural networks with softmax outputs requires assigning target values to output nodes. Due to its simplicity, we often use one-hot encoding, which adopts “one” or “zero” as the desired output values. However, when training neural networks to minimize the cross-entropy error function between the desired and actual output node values, overfitting of neural networks to training samples becomes a significant issue. A probabilistic target encoding has been proposed to mitigate the overfitting. In this paper, we derive the optimal solutions for output nodes that minimize the cross-entropy error function using the probabilistic target encoding. In the extreme case of the probabilistic target encoding, the analysis corresponds to the cross-entropy error function with one-hot encoding. The statistical analyses conducted to derive the optimal solutions provide considerable insights, including the interval of target values for the Bayes classifier.
