1__author__ = 'Thomas Rueckstiess, ruecksti@in.tum.de' 2 3from pybrain.structure.modules.neuronlayer import NeuronLayer 4 5class SoftSignLayer(NeuronLayer): 6 """ softsign activation function as described in X. Glorot and Y. 7 Bengio. Understanding the difficulty of training deep feedforward neural 8 networks. In Proceedings of the 13th International Workshop on 9 Artificial Intelligence and Statistics, 2010. """ 10 11 def _forwardImplementation(self, inbuf, outbuf): 12 outbuf[:] = inbuf / (1 + abs(inbuf)) 13 14 def _backwardImplementation(self, outerr, inerr, outbuf, inbuf): 15 inerr[:] = (1 - abs(outbuf))**2 * outerr 16