Mercurial > hg > camir-aes2014

annotate toolboxes/FullBNT-1.0.7/KPMstats/est_transmat.m @ 0:e9a9cd732c1e tip

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
first hg version after svn
author wolffd
date Tue, 10 Feb 2015 15:05:51 +0000
parents
children
rev   line source
wolffd@0 1 function [A,C] = est_transmat(seq)
wolffd@0 2 % ESTIMATE_TRANSMAT Max likelihood of a Markov chain transition matrix
wolffd@0 3 % [A,C] = estimate_transmat(seq)
wolffd@0 4 %
wolffd@0 5 % seq is a vector of positive integers
wolffd@0 6 %
wolffd@0 7 % e.g., seq = [1 2 1 2 3], C(1,2)=2, C(2,1)=1, C(2,3)=1, so
wolffd@0 8 % A(1,:)=[0 1 0], A(2,:) = [0.5 0 0.5],
wolffd@0 9 % all other entries are 0
wolffd@0 10
wolffd@0 11 % Use a trick with sparse matrices to count the number of each transition.
wolffd@0 12 % From http://www.mathworks.com/company/newsletter/may03/dna.shtml
wolffd@0 13
wolffd@0 14 C = full(sparse(seq(1:end-1), seq(2:end),1));
wolffd@0 15 A = mk_stochastic(C);