From 0f645836f193e75c4c3b718369e6fab15b5d19c5 Mon Sep 17 00:00:00 2001
From: Joseph Redmon <pjreddie@gmail.com>
Date: Wed, 11 Feb 2015 03:41:03 +0000
Subject: [PATCH] Detection is back, baby\!
---
src/activations.c | 76 ++++++++++++++++++++++++++++++++------
1 files changed, 64 insertions(+), 12 deletions(-)
diff --git a/src/activations.c b/src/activations.c
index b8bb79d..48dce87 100644
--- a/src/activations.c
+++ b/src/activations.c
@@ -2,8 +2,28 @@
#include <math.h>
#include <stdio.h>
+#include <stdlib.h>
#include <string.h>
+char *get_activation_string(ACTIVATION a)
+{
+ switch(a){
+ case SIGMOID:
+ return "sigmoid";
+ case RELU:
+ return "relu";
+ case RAMP:
+ return "ramp";
+ case LINEAR:
+ return "linear";
+ case TANH:
+ return "tanh";
+ default:
+ break;
+ }
+ return "relu";
+}
+
ACTIVATION get_activation(char *s)
{
if (strcmp(s, "sigmoid")==0) return SIGMOID;
@@ -15,34 +35,66 @@
return RELU;
}
-double activate(double x, ACTIVATION a){
+float linear_activate(float x){return x;}
+float sigmoid_activate(float x){return 1./(1. + exp(-x));}
+float relu_activate(float x){return x*(x>0);}
+float ramp_activate(float x){return x*(x>0)+.1*x;}
+float tanh_activate(float x){return (exp(2*x)-1)/(exp(2*x)+1);}
+//float tanh_activate(float x){return x - (x*x*x)/3;}
+
+float linear_gradient(float x){return 1;}
+float sigmoid_gradient(float x){return (1-x)*x;}
+float relu_gradient(float x){return (x>0);}
+float ramp_gradient(float x){return (x>0)+.1;}
+float tanh_gradient(float x){return 1-x*x;}
+
+float activate(float x, ACTIVATION a)
+{
switch(a){
case LINEAR:
- return x;
+ return linear_activate(x);
case SIGMOID:
- return 1./(1.+exp(-x));
+ return sigmoid_activate(x);
case RELU:
- return x*(x>0);
+ return relu_activate(x);
case RAMP:
- return x*(x>0) + .1*x;
+ return ramp_activate(x);
case TANH:
- return (exp(2*x)-1)/(exp(2*x)+1);
+ return tanh_activate(x);
}
return 0;
}
-double gradient(double x, ACTIVATION a){
+
+void activate_array(float *x, const int n, const ACTIVATION a)
+{
+ int i;
+ for(i = 0; i < n; ++i){
+ x[i] = activate(x[i], a);
+ }
+}
+
+float gradient(float x, ACTIVATION a)
+{
switch(a){
case LINEAR:
- return 1;
+ return linear_gradient(x);
case SIGMOID:
- return (1.-x)*x;
+ return sigmoid_gradient(x);
case RELU:
- return (x>0);
+ return relu_gradient(x);
case RAMP:
- return (x>0) + .1;
+ return ramp_gradient(x);
case TANH:
- return 1-x*x;
+ return tanh_gradient(x);
}
return 0;
}
+void gradient_array(const float *x, const int n, const ACTIVATION a, float *delta)
+{
+ int i;
+ for(i = 0; i < n; ++i){
+ delta[i] *= gradient(x[i], a);
+ }
+}
+
--
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