MATLAB: Customised output function for ga

gaoptimizationi

I have been looking how to create my own output function in GA to get each x and fval of each iteration and generation. Although I have looked into all the answered questions for such a question, nothing has been working so far. Here is my output function and please help me with what I'm missing.
function [state,options,optchanged] = gaoutfun(options,state,flag)
persistent history_pop history_Best history_Score
history_pop     = [];
history_Best    = [];
history_Score   = [];
optchanged = false;
switch flag
  case 'init'
          history_pop   = [history_pop;state.Population];
          assignin('base','gapopulationhistory',history_pop);
          history_Best  = [history_Best;state.Best];
          assignin('base','gabesthistory',history_Best);
          history_Score = [history_Score;state.Score];
          assignin('base','gascorehistory',history_Score);
    case 'iter'
          history_pop   = [history_pop;state.Population];
          assignin('base','gapopulationhistory',history_pop);
          history_Best  = [history_Best;state.Best];
          assignin('base','gabesthistory',history_Best);
          history_Score = [history_Score;state.Score];
          assignin('base','gascorehistory',history_Score);
    case 'done'
          history_pop   = [history_pop;state.Population];
          assignin('base','gapopulationhistory',history_pop);
          history_Best  = [history_Best;state.Best];
          assignin('base','gabesthistory',history_Best);
          history_Score = [history_Score;state.Score];
          assignin('base','gascorehistory',history_Score);        
end

Best Answer

function [state,options,optchanged] = gaoutfun(options,state,flag)
    persistent state_record 
    if isempty(state_record)
      state_record = struct('Population', {}, 'Best', {}, 'Score', {});
    end
    if nargin == 0
      state = state_record;
      options = [];
      optchanged = [];
    else
      state_record(end+1) = struct('Population', state.Population, 'Best', state.Best', 'Score', state.Score);
      optchanged = false;
    end
Before re-using this function, call
clear gaoutfun
Let the function be called as usual. Do not expect any changes outside the function when it is called.
After the ga run is finished, call
record = gaoutfun();
with no inputs. A structure of the state information will be returned.
However, this is likely to be a bit inefficient because the struct is expanded each iteration. I would suggest that when isempty() succeeds, that options be examined to find the maximum generations, and that state_record be initialized that large. Use state.Generation as the index for the output instead of end+1
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