If anyone is interested, I have a working neural net implementation https://github.com/btracey/nnet . I don't make any stability promises (especially on the training routines, that's a mess at the moment), but sometimes it's nice to see code. The core of the net is https://github.com/btracey/nnet/blob/master/nnet/functions.g... and https://github.com/btracey/nnet/blob/master/nnet/nnet.go