Mercurial > hg > camir-aes2014
diff toolboxes/FullBNT-1.0.7/KPMstats/est_transmat.m @ 0:e9a9cd732c1e tip
first hg version after svn
author | wolffd |
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date | Tue, 10 Feb 2015 15:05:51 +0000 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/toolboxes/FullBNT-1.0.7/KPMstats/est_transmat.m Tue Feb 10 15:05:51 2015 +0000 @@ -0,0 +1,15 @@ +function [A,C] = est_transmat(seq) +% ESTIMATE_TRANSMAT Max likelihood of a Markov chain transition matrix +% [A,C] = estimate_transmat(seq) +% +% seq is a vector of positive integers +% +% e.g., seq = [1 2 1 2 3], C(1,2)=2, C(2,1)=1, C(2,3)=1, so +% A(1,:)=[0 1 0], A(2,:) = [0.5 0 0.5], +% all other entries are 0 + +% Use a trick with sparse matrices to count the number of each transition. +% From http://www.mathworks.com/company/newsletter/may03/dna.shtml + +C = full(sparse(seq(1:end-1), seq(2:end),1)); +A = mk_stochastic(C);