www.pudn.com > ConstrainedEM.zip > best_params.m

% last modified by tomer 25.6 - solve situation when all 30 initial 
% conditions result in ll= -inf 
 
% last modified by noam 22.6 
% this best_params is intended to work only when labels are NOT available  
% or in they are not taken into consideration in choosing the initial conditions 
% see lines 18-20 
 
function res=... 
best_params(data,param,single_cov_mat_flag,dont_rand_covmat_flag,... 
chunks,ch_num,nc_inds,number_of_starts) 
% chooses the best out of number_of_trials random start params 
 
% returns the param variable sent, filled with the best parameters achieved 
% sets the centers and the cov-matrixes, not the weights 
 
% if the function is called without the last 3 params, no chunklets are assumed. 
% if the function is called without the last 2 params, they are calculated here. 
 
if ~exist('number_of_starts') 
    number_of_starts=30; 
end 
 
s=size(param); 
k=s(1); 
s=size(data); 
d=s(2);     % the dimension. 
n=s(1);     % the number of samples. 
 
 
if (nargin<7)					% chunklet information have to be calculated 
    if ~exist('chunks') 
      chunks=[]; 
   end 
 
   % this code is copied from mixture_of_gaussians2 
   if ~isempty(chunks)     % collect usful chunklets statistics. 
      ch_num=length(unique(chunks))-1; 
      for i=1:ch_num       
         chunk_sizes=length(find(chunks==i)); 
      end 
      number_of_hiddens=n-sum(chunk_sizes)+ch_num; 
      global nc_inds; 
      nc_inds=find(chunks==-1);   % nc_inds - non chunkletted data indexes 
   else                    % no chunklets 
      ch_num=0; 
      chunk_sizes=[]; 
      number_of_hiddens=n; 
      nc_inds=1:length(data); 
   end 
end 
 
if isempty(param{1,3})          %if there isn't initialization - initialize cluster weights 
   for i=1:k 
      param{i,3}=1/k; 
   end 
end 
 
 
% find the best params loop  
 
bll=-inf;       % best log liklihood. 
best= [];       % best params. 
 
i=1; 
infFlag= 1; 
 
while( (i <= number_of_starts) | (infFlag) ) 
%for i=1:number_of_starts tomer's chnage 
   set_start_params3; 
   [p , ll , c_p ]=calc_p_and_ll2(data,param,single_cov_mat_flag,chunks,ch_num,nc_inds); 
   if ll>=bll 
      bll=ll; 
      best=param; 
   end 
   i= i+1; 
   if(bll ~= -inf) 
     infFlag=0; 
   end 
    
end 
 
res=best;