From ac82bde55f3206a7a0d1b7a7580bea05096af32b Mon Sep 17 00:00:00 2001
From: Joseph Redmon <pjreddie@gmail.com>
Date: Thu, 17 Apr 2014 22:07:00 +0000
Subject: [PATCH] New feature extraction method
---
src/activations.c | 62 ++++++++++++++----------------
1 files changed, 29 insertions(+), 33 deletions(-)
diff --git a/src/activations.c b/src/activations.c
index a255f0f..c81d6aa 100644
--- a/src/activations.c
+++ b/src/activations.c
@@ -4,19 +4,39 @@
#include <stdio.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;
if (strcmp(s, "relu")==0) return RELU;
- if (strcmp(s, "identity")==0) return IDENTITY;
+ if (strcmp(s, "linear")==0) return LINEAR;
if (strcmp(s, "ramp")==0) return RAMP;
+ if (strcmp(s, "tanh")==0) return TANH;
fprintf(stderr, "Couldn't find activation function %s, going with ReLU\n", s);
return RELU;
}
-double activate(double x, ACTIVATION a){
+float activate(float x, ACTIVATION a){
switch(a){
- case IDENTITY:
+ case LINEAR:
return x;
case SIGMOID:
return 1./(1.+exp(-x));
@@ -24,12 +44,14 @@
return x*(x>0);
case RAMP:
return x*(x>0) + .1*x;
+ case TANH:
+ return (exp(2*x)-1)/(exp(2*x)+1);
}
return 0;
}
-double gradient(double x, ACTIVATION a){
+float gradient(float x, ACTIVATION a){
switch(a){
- case IDENTITY:
+ case LINEAR:
return 1;
case SIGMOID:
return (1.-x)*x;
@@ -37,35 +59,9 @@
return (x>0);
case RAMP:
return (x>0) + .1;
+ case TANH:
+ return 1-x*x;
}
return 0;
}
-double identity_activation(double x)
-{
- return x;
-}
-double identity_gradient(double x)
-{
- return 1;
-}
-
-double relu_activation(double x)
-{
- return x*(x>0);
-}
-double relu_gradient(double x)
-{
- return (x>0);
-}
-
-double sigmoid_activation(double x)
-{
- return 1./(1.+exp(-x));
-}
-
-double sigmoid_gradient(double x)
-{
- return x*(1.-x);
-}
-
--
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