octave_packages/ga-0.10.0/__ga_initial_population__.m

   1 ## Copyright (C) 2008, 2010 Luca Favatella <slackydeb@gmail.com>
   2 ##
   3 ## This program is free software; you can redistribute it and/or modify
   4 ## it under the terms of the GNU General Public License as published by
   5 ## the Free Software Foundation; either version 2 of the License, or
   6 ## (at your option) any later version.
   7 ##
   8 ## This program is distributed in the hope that it will be useful,
   9 ## but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 ## GNU General Public License for more details.
  12 ##
  13 ## You should have received a copy of the GNU General Public License
  14 ## along with this program; If not, see <http://www.gnu.org/licenses/>.
  15
  16 ## -*- texinfo -*-
  17 ## @deftypefn{Function File} {@var{Population} =} __ga_initial_population__ (@var{GenomeLength}, @var{FitnessFcn}, @var{options})
  18 ## Create an initial population.
  19 ##
  20 ## @seealso{__ga_problem__}
  21 ## @end deftypefn
  22
  23 ## Author: Luca Favatella <slackydeb@gmail.com>
  24 ## Version: 3.3
  25
  26                                 #TODO consider PopulationSize as a
  27                                 #vector for multiple subpopolations
  28
  29 function Population = \
  30       __ga_initial_population__ (GenomeLength, FitnessFcn, options)
  31   if (isempty (options.InitialPopulation))
  32     Population(1:options.PopulationSize, 1:GenomeLength) = \
  33         options.CreationFcn (GenomeLength, FitnessFcn, options);
  34   else
  35     if (columns (options.InitialPopulation) != GenomeLength) ## columns (InitialPopulation) > 0
  36       error ("nonempty 'InitialPopulation' must have 'GenomeLength' columns");
  37     else ## rows (InitialPopulation) > 0
  38       nrIP = rows (options.InitialPopulation);
  39       if (nrIP > options.PopulationSize)
  40         error ("nonempty 'InitialPopulation' must have no more than \
  41             'PopulationSize' rows");
  42       elseif (nrIP == options.PopulationSize)
  43         Population(1:options.PopulationSize, 1:GenomeLength) = \
  44             options.InitialPopulation;
  45       else # rows (InitialPopulation) < PopulationSize
  46
  47         ## create a complete new population, and then select only needed
  48         ## individuals (creating only a partial population is difficult)
  49         CreatedPopulation(1:options.PopulationSize, 1:GenomeLength) = \
  50             options.CreationFcn (GenomeLength, FitnessFcn, options);
  51         Population(1:options.PopulationSize, 1:GenomeLength) = vertcat \
  52             (options.InitialPopulation(1:nrIP, 1:GenomeLength),
  53              CreatedPopulation(1:(options.PopulationSize - nrIP),
  54                                1:GenomeLength));
  55       endif
  56     endif
  57   endif
  58 endfunction
  59
  60
  61 %!test
  62 %! GenomeLength = 2;
  63 %! options = gaoptimset ();
  64 %! Population = __ga_initial_population__ (GenomeLength, @rastriginsfcn, options);
  65 %! assert (size (Population), [options.PopulationSize, GenomeLength]);
  66
  67 %!test
  68 %! GenomeLength = 2;
  69 %! options = gaoptimset ("InitialPopulation", [1, 2; 3, 4; 5, 6]);
  70 %! Population = __ga_initial_population__ (GenomeLength, @rastriginsfcn, options);
  71 %! assert (size (Population), [options.PopulationSize, GenomeLength]);
  72
  73
  74 ## nonempty 'InitialPopulation' must have 'GenomeLength' columns
  75
  76 %!error
  77 %! GenomeLength = 2;
  78 %! options = gaoptimset ("InitialPopulation", [1; 3; 5]);
  79 %! __ga_initial_population__ (GenomeLength, @rastriginsfcn, options);
  80
  81 %!error
  82 %! GenomeLength = 2;
  83 %! options = gaoptimset ("InitialPopulation", [1, 1, 1; 3, 3, 3; 5, 5, 5]);
  84 %! __ga_initial_population__ (GenomeLength, @rastriginsfcn, options);
  85
  86
  87 ## nonempty 'InitialPopulation' must have no more than 'PopulationSize' rows
  88
  89 %!error
  90 %! GenomeLength = 2;
  91 %! options = gaoptimset ("InitialPopulation", [1, 2; 3, 4; 5, 6], "PopulationSize", 2);
  92 %! __ga_initial_population__ (GenomeLength, @rastriginsfcn, options);