Softmax fails on array of TrackedReal

[mboedigh]

I first noticed this problem with Flux 0.8.2, but it may have existed in earlier versions.

using Flux
tracked_array = Flux.param(Flux.glorot_uniform(10,3)); # tracked array of reals
Flux.softmax(tracked_array) # all good

array_of_tracked_reals = reduce(hcat, [tracked_array,tracked_array]);
Flux.softmax(array_of_tracked_reals) # fails with MethodError: no method matching softmax!(...)

I can get around it using hcat(...) #with splats, which creates a tracked_array of reals, but I would also like to use the array of tracked reals for other reasons.

[thebhatman]

I think this has been fixed on NNlib master. This line https://github.com/FluxML/NNlib.jl/blob/40cee4b01021dfb1a6a14ba6dc05be636d05af1f/src/softmax.jl#L22 shows the correct way. Older versions of NNlib have where {T} <: AbstractFloat in this particular line which was the cause of the problem. Changing this to where {T} will make softmax work on an array of TrackedReals.