modified sigmoid to improve numerical stability

sth4nth · sth4nth · commit 6aca8a7ae56a · 2016-01-27T16:29:35.000+08:00
diff --git a/chapter04/sigmoid.m b/chapter04/sigmoid.m
@@ -1,4 +1,4 @@
 function y = sigmoid(x)
 % Sigmod function
 % Written by Mo Chen (sth4nth@gmail.com).
-y = 1./(1+exp(-x));
+y = exp(-log1pexp(-x));
diff --git a/chapter13/HMM/demo.m b/chapter13/HMM/demo.m
@@ -2,7 +2,7 @@
 
 d = 3;
 k = 2;
-n = 1000;
+n = 10000;
 
 [x, model] = hmmRnd(d, k, n);
 [z, v] = hmmViterbi(x,model);
diff --git a/chapter13/LDS/demo.m b/chapter13/LDS/demo.m
@@ -1,6 +1,6 @@
 % demo
 d = 3;
-k = 2;
+k = 3;
 n = 10000;
 
 [X,model] = ldsRnd(d,k,n);

-Original file line number
+Diff line change
@@ @@ -1,6 +1,6 @@ @@
 % demo
 d = 3;
 -k = 2;
 +k = 3;
 n = 10000;
 [X,model] = ldsRnd(d,k,n);