shufflestates.m

HMMBOX, version 3.2, William Penny, Imperial College, Feb 1999 Matlab toolbox for Hidden Markov Mod

function [sortsequence,map] = shufflestates(ipsequence,refsequence)
% [sortsequence,map] = shufflestates(ipsequence,refsequence)
%
% shuffles state sequences such that a heuristically esimtated
% permutation matrix between the label distributions is minised
% 
% Input
%  ipsequence      input label sequence
%  refsequence     reference label sequence
%                  (if missing uses ipsequence instead)
% Output
% sortsequence     reshuffles input sequence
% map              mapping used for reshuffling
%
%


ipsequence=ipsequence(:);
ipclabels=unique(ipsequence);
Kip=length(ipclabels);
ipclabpdf=hist(ipsequence,ipclabels);

if nargin<2
  refclabpdf=sort(ipclabpdf);
  Kref=Kip;
else
  refsequence=refsequence(:);

  refclabels=unique(refsequence);
  Kref=length(refclabels);
  refclabpdf=hist(refsequence,refclabels)
end;


map=[];
for i=1:Kip,
  [tmp,pos]=min(abs(ipclabpdf(i)-refclabpdf));
  if ~ismember(pos,map)
    map=[map pos];
  end
end;
map=[map setdiff(1:Kip,map)];


sortsequence=map(ipsequence);