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authorziejd22018-03-14 23:23:33 -0500
committerGitHub2018-03-14 23:23:33 -0500
commit1ff6baa44e22b91eefb48aea6f3befa078c0489b (patch)
treee0fd79d2e32fd2aedda2eadaed0f19af3514c520 /sourcecodes/bnt-master/KPMtools/logsumexp.m
parent6882395afdadf4e982b25b5215071a0932730950 (diff)
parentc80226899f5cdd9f11c163817d59445213f5bef0 (diff)
downloadBNW-1ff6baa44e22b91eefb48aea6f3befa078c0489b.tar.gz
Merge pull request #1 from ziejd2/octave_php_separate
Octave php separate
Diffstat (limited to 'sourcecodes/bnt-master/KPMtools/logsumexp.m')
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diff --git a/sourcecodes/bnt-master/KPMtools/logsumexp.m b/sourcecodes/bnt-master/KPMtools/logsumexp.m
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+function s = logsumexp(a, dim)
+% Returns log(sum(exp(a),dim)) while avoiding numerical underflow.
+% Default is dim = 1 (rows) or dim=2 for a row vector
+% logsumexp(a, 2) will sum across columns instead of rows
+
+% Written by Tom Minka, modified by Kevin Murphy
+
+if nargin < 2
+  dim = 1;
+  if ndims(a) <= 2 & size(a,1)==1
+    dim = 2;
+  end
+end
+
+% subtract the largest in each column
+[y, i] = max(a,[],dim);
+dims = ones(1,ndims(a));
+dims(dim) = size(a,dim);
+a = a - repmat(y, dims);
+s = y + log(sum(exp(a),dim));
+%i = find(~finite(y));
+%if ~isempty(i)
+%  s(i) = y(i);
+%end