#include "activations.h"
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#include <math.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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char *get_activation_string(ACTIVATION a)
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{
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switch(a){
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case SIGMOID:
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return "sigmoid";
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case RELU:
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return "relu";
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case RAMP:
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return "ramp";
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case LINEAR:
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return "linear";
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case TANH:
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return "tanh";
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default:
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break;
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}
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return "relu";
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}
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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, "linear")==0) return LINEAR;
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if (strcmp(s, "ramp")==0) return RAMP;
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if (strcmp(s, "tanh")==0) return TANH;
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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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float linear_activate(float x){return x;}
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float sigmoid_activate(float x){return 1./(1. + exp(-x));}
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float relu_activate(float x){return x*(x>0);}
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float ramp_activate(float x){return x*(x>0)+.1*x;}
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float tanh_activate(float x){return (exp(2*x)-1)/(exp(2*x)+1);}
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float activate(float x, ACTIVATION a, float dropout)
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{
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if(dropout && (float)rand()/RAND_MAX < dropout) return 0;
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switch(a){
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case LINEAR:
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return linear_activate(x)/(1-dropout);
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case SIGMOID:
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return sigmoid_activate(x)/(1-dropout);
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case RELU:
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return relu_activate(x)/(1-dropout);
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case RAMP:
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return ramp_activate(x)/(1-dropout);
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case TANH:
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return tanh_activate(x)/(1-dropout);
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}
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return 0;
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}
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void activate_array(float *x, const int n, const ACTIVATION a, float dropout)
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{
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int i;
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for(i = 0; i < n; ++i){
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x[i] = activate(x[i], a, dropout);
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}
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}
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float gradient(float x, ACTIVATION a){
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switch(a){
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case LINEAR:
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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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case TANH:
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return 1-x*x;
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}
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return 0;
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}
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void gradient_array(const float *x, const int n, const ACTIVATION a, float *delta)
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{
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int i;
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for(i = 0; i < n; ++i){
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delta[i] *= gradient(x[i], a);
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}
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}
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#ifdef GPU
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#include "opencl.h"
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#include <math.h>
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cl_kernel get_activation_kernel()
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{
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static int init = 0;
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static cl_kernel kernel;
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if(!init){
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kernel = get_kernel("src/activations.cl", "activate_array", 0);
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init = 1;
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}
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return kernel;
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}
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void activate_array_ongpu(cl_mem x, int n, ACTIVATION a, float dropout)
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{
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cl_setup();
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cl_kernel kernel = get_activation_kernel();
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cl_command_queue queue = cl.queue;
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cl_uint i = 0;
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cl.error = clSetKernelArg(kernel, i++, sizeof(x), (void*) &x);
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cl.error = clSetKernelArg(kernel, i++, sizeof(n), (void*) &n);
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cl.error = clSetKernelArg(kernel, i++, sizeof(a), (void*) &a);
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cl.error = clSetKernelArg(kernel, i++, sizeof(dropout),
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(void*) &dropout);
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check_error(cl);
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size_t gsize = n;
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clEnqueueNDRangeKernel(queue, kernel, 1, 0, &gsize, 0, 0, 0, 0);
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check_error(cl);
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}
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#endif
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