comparison solvers/SMALL_cgp.m @ 22:524cc3fff5ac

(none)

 function [A, resF]=SMALL_cgp(Dict,X, m,  maxNumCoef, errorGoal, varargin) 
-%=============================================
+%%% Conjugate Gradient Pursuit Multiple vectors sparse representation
+%
+%   Centre for Digital Music, Queen Mary, University of London.
+%   This file copyright 2009 Ivan Damnjanovic.
+%
+%   This program is free software; you can redistribute it and/or
+%   modify it under the terms of the GNU General Public License as
+%   published by the Free Software Foundation; either version 2 of the
+%   License, or (at your option) any later version.  See the file
+%   COPYING included with this distribution for more information.
+%   
 % Sparse coding of a group of signals based on a given 
 % dictionary and specified number of atoms to use. 
 % input arguments: Dict - the dictionary
 %                  X - the signals to represent
 %                  m - number of atoms in Dictionary

 % optional:        if Dict is function handle then Transpose Dictionary
 %                  handle needs to be specified.
 %
 % output arguments: A - sparse coefficient matrix.
 %
-% based on KSVD toolbox solver found on Miki Elad webpage (finding inverse
-% with pinv() is changed with conjugate gradient method)
-% Ivan Damnjanovic 2009
-%=============================================
-%%
 %%
 
 % This Dictionary check is based on Thomas Blumensath work in sparsify 0_4 greedy solvers 
 if     isa(Dict,'float')      
             D =@(z) Dict*z;  

     end
 else
     error('Dictionary is of unsupported type. Use explicit matrix, function_handle or object. Exiting.');
 end
 %%
-
+positivity=1;
 [n,P]=size(X);
 
 
 
 A = sparse(m,size(X,2));

     
     while  j < maxNumCoef,
         
         j = j+1;
         dir=Dt(residual);
-        
-        [tmp__, pos]=max(abs(dir));
+        if exist('positivity','var')&&(positivity==1)
+            [tmp__, pos]=max(dir);
+        else
+            [tmp__, pos]=max(abs(dir));
+        end
         indx(j)=pos;
         
         p(indx)=dir(indx);
         Dp=D(p);
         pDDp=Dp'*Dp;