Does SoftmaxLayer not support back-propagation because you haven't needed that functionality yet, perhaps because softmax is usually followed by a logistic loss, and you can use SoftmaxLossLayer instead? (Do you mainly use SoftmaxLayer to normalized blobs from a data layer?) Or is implementing back-propagation for SoftmaxLayer likely to be challenging (or to not scale well) from some reason? I'll work on it and submit a PR if you don't foresee any problems.
@jeff-regier back propagation for softmax is actually implemented a while ago. Sorry I forgot to update the document. Just updated it! Thanks for reporting!
Does
SoftmaxLayer
not support back-propagation because you haven't needed that functionality yet, perhaps because softmax is usually followed by a logistic loss, and you can useSoftmaxLossLayer
instead? (Do you mainly useSoftmaxLayer
to normalized blobs from a data layer?) Or is implementing back-propagation forSoftmaxLayer
likely to be challenging (or to not scale well) from some reason? I'll work on it and submit a PR if you don't foresee any problems.