add lognormexp

common/lognormexp.m

@@ -0,0 +1,10 @@
+function [Y,s] = lognormexp(X, dim)
+% Compute log(normalize(exp(x),dim)) while avoiding numerical underflow.
+%   By default dim = 1 (columns).
+% Written by Mo Chen ([email protected]).
+if nargin == 1
+    dim = find(size(X)~=1,1);
+    if isempty(dim), dim = 1; end
+end
+s = logsumexp(X,dim);
+Y = exp(X-s);