/*
libcudann
Copyright (C) 2011 Luca Donati (lucadonati85@gmail.com)
*/
/*
* ActivationFunctions.h
*
* Created on: Nov 24, 2010
* Author: donati
*/
#ifndef ACTIVATIONFUNCTIONS_H_
#define ACTIVATIONFUNCTIONS_H_
#define ACT_LINEAR 0
#define ACT_SIGMOID 1
#define ACT_TANH 2
//returns the value of the activation function
float actFunction(int act, float x);
//returns the value of the activation function derivation (used for backpropagation)
float actDerivation(int act, float y);
//returns the span size of a function for error calculation
float spanSize(int act);
/*//old macros
#define clip(x, lo, hi) (((x) < (lo)) ? (lo) : (((x) > (hi)) ? (hi) : (x)))
#define spanSize(act)(\
act == ACT_TANH ? 2:\
1\
)
#define actFunction(act, x)(\
act == ACT_LINEAR ? x :\
act == ACT_SIGMOID ? 1.0f/(1.0f+exp(-x)) :\
act == ACT_TANH ? 2.0f/(1.0f+exp(-x))-1.0f :\
0\
)
#define actDerivation(act, y)(\
act == ACT_LINEAR ? 1 :\
act == ACT_SIGMOID ? clip(y,0.01f,0.99f)*(1.0f-clip(y,0.01f,0.99f)) :\
act == ACT_TANH ? 0.5f*(1.0f-(clip(y,-0.98f,0.98f)*clip(y,-0.98f,0.98f))) :\
0\
)
*/
#endif /* ACTIVATIONFUNCTIONS_H_ */