% -------------------------------------------------------------
% GA FOR MIXTURE MODELS, function implementing the tournament selection

% Copyright (c) 2005 - 2006 Jussi Tohka (jussi.tohka@tut.fi)
% Institute of Signal Processing, Tampere University of Technology, Finland
% and
% Laboratory of Neuro Imaging, David Geffen School of Medicine,
% University of California, Los Angeles, CA, USA 

% The algorithm is described in :
% Tohka J, Krestyannikov E, Dinov ID, MacKenzie-Graham A, Shattuck DW,
% Ruotsalainen U, Toga AW: 
% Genetic Algorithms for Finite Mixture Model Based Voxel Classification 
% in Neuroimaging, accepted to appear in IEEE Trans. on Medical Imaging,
% 2007
% and
% J. Tohka, E. Krestyannikov, I. Dinov, D. Shattuck, U. Ruotsalainen,
% A.W. Toga. Genetic algorithms for finite mixture model based tissue
% classification in brain MRI. In  Proc. of European Medical and
% Biological Engineering Conference, IFMBE Proceedings vol. 11, pp. 4077
% - 4082, Prague, Czech Republic, 2005.
% ----------------------------------------------------------------
% Permission to use, copy, modify, and distribute this software 
% for any purpose and without fee is hereby
% granted, provided that the above copyright notice appear in all
% copies.  The author, Tampere University of Technology and University of
% California, Los Angeles make no representations
% about the suitability of this software for any purpose.  It is
% provided "as is" without express or implied warranty.
% ---------------------------- ---------------------------------
% n is how many to select
% q is the size of the tournament

function  new_pop = mixturega_tournamentselection(old_pop,energies,n,q);
  popsz = size(old_pop);
  % tournaments = unidrnd(popsz(2),q,n);
  tournaments =  ceil(popsz(2) .* rand([q n]));
  [minene minind] = min(energies(tournaments));
  indvector = diag(tournaments(minind,1:n));
  new_pop = old_pop(:,indvector);