From ace5aeb0f59fdceb99e607af9780added20da37c Mon Sep 17 00:00:00 2001
From: Joseph Redmon <pjreddie@gmail.com>
Date: Fri, 24 Jan 2014 22:51:17 +0000
Subject: [PATCH] MNIST connected network showing off matrices
---
src/activations.c | 60 ++++++++++++++++++++++++++++++++++++++----------------------
1 files changed, 38 insertions(+), 22 deletions(-)
diff --git a/src/activations.c b/src/activations.c
index aef21cb..b8bb79d 100644
--- a/src/activations.c
+++ b/src/activations.c
@@ -1,32 +1,48 @@
#include "activations.h"
#include <math.h>
+#include <stdio.h>
+#include <string.h>
-double identity_activation(double x)
+ACTIVATION get_activation(char *s)
{
- return x;
-}
-double identity_gradient(double x)
-{
- return 1;
+ if (strcmp(s, "sigmoid")==0) return SIGMOID;
+ if (strcmp(s, "relu")==0) return RELU;
+ 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 relu_activation(double x)
-{
- return x*(x>0);
+double activate(double x, ACTIVATION a){
+ switch(a){
+ case LINEAR:
+ return x;
+ case SIGMOID:
+ return 1./(1.+exp(-x));
+ case RELU:
+ 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 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);
+double gradient(double x, ACTIVATION a){
+ switch(a){
+ case LINEAR:
+ return 1;
+ case SIGMOID:
+ return (1.-x)*x;
+ case RELU:
+ return (x>0);
+ case RAMP:
+ return (x>0) + .1;
+ case TANH:
+ return 1-x*x;
+ }
+ return 0;
}
--
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