% OBJPUSH.M      (OBJective function for PUSH-cart problem)%% This function implements the PUSH-CART PROBLEM.%% Syntax:  ObjVal = objpush(Chrom,switch_)%% 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%    switch_    - if Chrom == [] and%                switch_ == 1 (or []) return boundaries%                switch_ == 2 return title%                switch_ == 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%                switch_ == 1, matrix with the boundaries of the function%                switch_ == 2, text for the title of the graphic output%                switch_ == 3, value of global minimum%                % Author:     Hartmut Pohlheim% History:    19.02.94     file created (copy of valharv.m)%             01.03.94     name changed in obj*function ObjVal = objpush(Chrom,switch_);% Dimension of objective function   Dim = 20;% values from MICHALEWICZ   x0 = [0 0];   % Compute population parameters   [Nind,Nvar] = size(Chrom);% Check size of Chrom and do the appropriate thing   % if Chrom is [], then define size of boundary-matrix and values   if Nind == 0      % return text of title for graphic output      if switch_ == 2         ObjVal = ['PUSH-CART PROBLEM-' int2str(Dim)];      % return value of global minimum      elseif switch_ == 3         ObjVal = -(1/3 - ((3*Dim-1)/(6*Dim^2)) - (1/(2*Dim^3))*sum((1:Dim-1).^2));      % define size of boundary-matrix and values      else            % lower and upper bound, identical for all n variables                 ObjVal = [0; 5];         ObjVal = rep(ObjVal,[1 Dim]);      end   % if Dim variables, compute values of function   elseif Nvar == Dim      ObjVal = zeros(Nind,1);      X = rep(x0,[Nind 1]);      for irun = 1:Nvar,         Xsave = X;         X(:,1) = Xsave(:,2);         X(:,2) = 2 * X(:,2) - Xsave(:,1) + (1/Dim^2) * Chrom(:,irun);      end      X;      ObjVal = -(X(:,1) - (1/(2*Dim)) * sum((Chrom.^2)')');   % otherwise error, wrong format of Chrom   else      error('size of matrix Chrom is not correct for function evaluation');   end   % End of function