www.pudn.com > geneticbs2rv.rar > RECMUT.M

% RECLIN.M       (line RECombination with MUTation features) 
% 
% This function performs line recombination with mutation features between 
% pairs of individuals and returns the new individuals after mating. 
% 
% Syntax:  NewChrom = recmut(OldChrom, FieldDR, MutOpt) 
% 
% Input parameters: 
%    OldChrom  - Matrix containing the chromosomes of the old 
%                population. Each line corresponds to one individual 
%    FieldDR   - Matrix describing the boundaries of each variable. 
%    MutOpt    - (optional) Vector containing recombination rate and shrink value 
%                MutOpt(1): MutR - number containing the recombination rate - 
%                           probability for recombine a pair of parents 
%                           if omitted or NaN, MutOpt(1) = 1 is assumed 
%                MutOpt(2): MutShrink - (optional) number for shrinking the 
%                           recombination range in the range [0 1], possibility to 
%                           shrink the range of the recombination depending on, 
%                           for instance actual generation. 
%                           if omitted or NaN, MutOpt(2) = 1 is assumed 
% 
% Output parameter: 
%    NewChrom - Matrix containing the chromosomes of the population 
%               after mating, ready to be mutated and/or evaluated, 
%               in the same format as OldChrom. 
 
%  Author:    Hartmut Pohlheim 
%  History:   27.03.94     file created 
 
function NewChrom = recmut(OldChrom, FieldDR, MutOpt); 
 
% Check parameter consistency 
   if nargin < 2,  error('Not enough input parameter'); end 
 
   % Identify the population size (Nind) and the number of variables (Nvar) 
   [Nind,Nvar] = size(OldChrom); 
 
   [mF, nF] = size(FieldDR); 
   if mF ~= 2, error('FieldDR must be a matrix with 2 rows'); end 
   if Nvar ~= nF, error('FieldDR and OldChrom disagree'); end 
 
   if nargin < 3, MutR = 1; MutShrink = 1; 
   elseif isempty(MutOpt), MutR = 1; MutShrink = 1; 
   elseif isnan(MutOpt), MutR = 1; MutShrink = 1; 
   else    
      if length(MutOpt) == 1, MutR = MutOpt; MutShrink = 1; 
      elseif length(MutOpt) == 2, MutR = MutOpt(1); MutShrink = MutOpt(2); 
      else, error(' Too many parameter in MutOpt'); end 
   end 
 
   if isempty(MutR), MutR = 1; 
   elseif isnan(MutR), MutR = 1; 
   elseif length(MutR) ~= 1, error('Parameter for recombination rate must be a scalar'); 
   elseif (MutR < 0 | MutR > 1), error('Parameter for recombination rate must be a scalar in [0, 1]'); end 
 
   if isempty(MutShrink), MutShrink = 1; 
   elseif isnan(MutShrink), MutShrink = 1; 
   elseif length(MutShrink) ~= 1, error('Parameter for shrinking recombination range must be a scalar'); 
   elseif (MutShrink < 0 | MutShrink > 1),  
      error('Parameter for shrinking recombination range must be a scalar in [0, 1]'); 
   end 
 
% Identify the number of matings 
   Xops = floor(Nind/2); 
 
% NewChrom = OldChrom (+ or -) * Range * MutShrink * Delta * ChromDiff 
% - with probability 0.9, + with probability 0.1 
% Range = 0.5 * (upperbound - lowerbound), given by FieldDR 
% Delta = Sum(Alpha_i * 2^-i) from 0 to ACCUR; Alpha_i = rand(ACCUR,1) < 1/ACCUR 
% ChromDiff = (individual1 - individual2) / Distance between individuals  
 
% Matrix with range values for every variable 
   Range = rep(0.5 * MutShrink *(FieldDR(2,:)-FieldDR(1,:)),[Xops 1]); 
 
% zeros and ones for recombine or not this variable, together with Range 
   if MutR < 1, Range = Range .* rep((rand(Xops,1) < MutR), [1 Nvar]); end 
 
% compute, if + or - sign  
   Range = Range .* (1 - 2 * (rand(Xops,Nvar) < 0.9)); 
 
% compute distance between mating pairs 
   NormO = zeros(Xops,1); 
   for irun = 1:Xops, 
      NormO(irun) = max(realmin,abs(norm(OldChrom(2*irun,:)) - norm(OldChrom(2*irun-1,:)))); 
   end 
 
% compute difference between variables divided by distance 
   ChromDiff = zeros(Xops,Nvar); 
   for irun = 1:Xops 
      ChromDiff(irun,:) = diff([OldChrom(2*irun-1,:); OldChrom(2*irun,:)]) / NormO(irun); 
   end 
 
% compute delta value for all individuals 
   ACCUR = 20; 
   Vect = 2 .^ (-(0:(ACCUR-1))'); 
   Delta = (rand(Xops,ACCUR) < 1/ACCUR) * Vect; 
   Delta = rep(Delta, [1 Nvar]); 
 
% Performs recombination 
   odd = 1:2:Nind-1; 
   even= 2:2:Nind; 
 
   % recombination 
   NewChrom(odd,:)  = OldChrom(odd,:) + Range .* Delta .* (ChromDiff); 
   NewChrom(even,:)  = OldChrom(even,:) + Range .* Delta .* (-ChromDiff); 
 
% If the number of individuals is odd, the last individual cannot be mated 
% but must be included in the new population 
   if rem(Nind,2),  NewChrom(Nind,:)=OldChrom(Nind,:); end 
 
% Ensure variables boundaries, compare with lower and upper boundaries 
   NewChrom = max(rep(FieldDR(1,:),[Nind 1]), NewChrom); 
   NewChrom = min(rep(FieldDR(2,:),[Nind 1]), NewChrom); 
 
 
% End of function