Documentation of objeaso

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Function Synopsis

ObjVal = objeaso(Chrom, option);

Help text

 OBJective function for EASom function

 This function implements the EASOM function.

 Syntax:  ObjVal = objeaso(Chrom, option)

 Input parameters:
    Chrom     - Matrix containing the chromosomes of the current
                population. Each row corresponds to one individual's
                string representation.
                if Chrom == [], then speziell values will be returned
    option    - if Chrom == [] and
                option == 1 (or []) return boundaries
                option == 2 return title
                option == 3 return value of global minimum

 Output parameters:
    ObjVal    - Column vector containing the objective values of the
                individuals in the current population.
                if called with Chrom == [], then ObjVal contains
                option == 1, matrix with the boundaries of the function
                option == 2, text for the title of the graphic output
                option == 3, value of global minimum
                
 See also: objbran, objsixh, objgold, obj*

Cross-Reference Information

Listing of function objeaso

% Author:     Hartmut Pohlheim
% History:    25.11.93     file created
%             27.11.93     text of title and option added
%             16.12.93     option == 3, return value of global minimum
%             01.03.94     name changed in obj*
%             17.02.95     function cleaned


function ObjVal = objeaso(Chrom, option);

% Compute population parameters
   [Nind, Nvar] = size(Chrom);

% Check size of Chrom and do the appropriate thing
   % if Chrom is []
   if Nind == 0
      % return text of title for graphic output
      if option == 2
         ObjVal = 'EASOMs function';
      % return value of global minimum
      elseif option == 3
         ObjVal = -1;
      % define size of boundary-matrix and values
      else   
         %         x1 x2
         ObjVal = [-100 -100;  % lower bounds
                    100  100]; % upper bounds
      end            
   % if two variables, compute values of function
   elseif Nvar == 2
      % EASOM's function
      % -100(-5) <= x1 <= 100(5) ; -100(-5) <= x2 <= 100(5)
      % global minimum at (x1,x2)=(pi,pi) ; fmin=-1
      x1 = Chrom(:,1);
      x2 = Chrom(:,2);
      ObjVal = -cos(x1).*cos(x2).*exp(-((x1-pi).^2+(x2-pi).^2));
   % otherwise error, wrong format of Chrom
   else
      error('size of matrix Chrom is not correct for function evaluation');
   end   


% End of function