#include "activations.h"
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#include <math.h>
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#include <stdio.h>
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#include <string.h>
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ACTIVATION get_activation(char *s)
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{
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if (strcmp(s, "sigmoid")==0) return SIGMOID;
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if (strcmp(s, "relu")==0) return RELU;
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if (strcmp(s, "identity")==0) return IDENTITY;
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if (strcmp(s, "ramp")==0) return RAMP;
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fprintf(stderr, "Couldn't find activation function %s, going with ReLU\n", s);
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return RELU;
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}
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double activate(double x, ACTIVATION a){
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switch(a){
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case IDENTITY:
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return x;
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case SIGMOID:
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return 1./(1.+exp(-x));
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case RELU:
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return x*(x>0);
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case RAMP:
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return x*(x>0) + .1*x;
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}
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return 0;
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}
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double gradient(double x, ACTIVATION a){
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switch(a){
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case IDENTITY:
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return 1;
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case SIGMOID:
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return (1.-x)*x;
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case RELU:
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return (x>0);
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case RAMP:
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return (x>0) + .1;
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}
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return 0;
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}
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double identity_activation(double x)
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{
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return x;
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}
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double identity_gradient(double x)
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{
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return 1;
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}
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double relu_activation(double x)
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{
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return x*(x>0);
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}
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double relu_gradient(double x)
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{
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return (x>0);
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}
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double sigmoid_activation(double x)
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{
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return 1./(1.+exp(-x));
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}
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double sigmoid_gradient(double x)
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{
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return x*(1.-x);
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}
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