[irstlm] 57/126: added supporting functions

[Giulio Paci]

This is an automated email from the git hooks/post-receive script.

giuliopaci-guest pushed a commit to annotated tag adaptiveLM.v0.1
in repository irstlm.

commit 98e1b65b8e09fca4cc0871e15858514b2a3fddb5
Author: Nicola Bertoldi <bertoldi at fbk.eu>
Date:   Wed Sep 9 17:05:58 2015 +0200

    added supporting functions
---
 src/util.cpp | 25 ++++++++++++++++++++++++-
 src/util.h   |  4 ++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/src/util.cpp b/src/util.cpp
index b25f3ea..665287e 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -380,9 +380,32 @@ float logsum(float a,float b){
 	else return b + logf(1+ expf(a-b));
 }
 
+float log10sum(float a,float b){
+	if (b<a) return a + log10(1 + pow(10.0,(b-a)));
+	else return b + log10(1 + pow(10.0,(a-b)));
+}
+
 double logsum(double a,double b){
 	if (b<a) return a + log(1 + exp(b-a));
-	else return b + log(1+ exp(a-b));
+	else return b + log(1 + exp(a-b));
+}
+
+double log10sum(double a,double b){
+	if (b<a) return a + log10(1 + pow(10.0,(b-a)));
+	else return b + log10(1 + pow(10.0,(a-b)));
 }
 
 
+double logistic_function(double x, double max, double steep)
+{
+	//domain: (-inf, +inf)
+	//image: [0,max)
+	//logistic_function(0.0,max,steep) = max/2
+	//lim_{x->+inf} logistic_function(x,max,steep) = max
+	//lim_{x->-inf} logistic_function(x,max,steep) = 0
+	//if steep1>steep2, then
+	// logistic_function(x,max,steep1) > logistic_function(x,max,steep2)   if x>0
+	// logistic_function(x,max,steep1) < logistic_function(x,max,steep2)   if x<0
+
+	return max/1+exp(-steep*x);
+}
diff --git a/src/util.h b/src/util.h
index 694a485..c49db09 100644
--- a/src/util.h
+++ b/src/util.h
@@ -104,7 +104,11 @@ extern const int tracelevel;
 void MY_ASSERT(bool x);
 
 float logsum(float a,float b);
+float log10sum(float a,float b);
 double logsum(double a,double b);
+double log10sum(double a,double b);
+
+double logistic_function(double x, double max=1.0, double steep=1.0);
 
 #endif
 

-- 
Alioth's /usr/local/bin/git-commit-notice on /srv/git.debian.org/git/debian-science/packages/irstlm.git