initpop.m

本程序是基于matlab的时间序列预测模型GP源程序

function popu = initpop(popusize,maxtreedepth,symbols);
% 初始化种群个体

popu.generation = 1;
popu.symbols = symbols;
popu.size = popusize;
for i = 1:popu.size,
  popu.chrom{i}.fitness = 0;
  popu.chrom{i}.mse = 0;
  popu.chrom{i}.tree = tree_genrnd(maxtreedepth,symbols);
end
return

% -------------------------------------------------------------------------
function tree = tree_genrnd(maxtreedepth,symbols);
% 随机生成二叉树

nn = [length(symbols{1}), length(symbols{2})];
n =2^floor(maxtreedepth)-1;
vt = zeros(n,1);
vn = zeros(n,1);
for i=1:(n-1)/2,
  [vt(i) vn(i)] = tree_genrndsymb(1/2,nn);
end
for i=(n+1)/2:n,
  [vt(i) vn(i)] = tree_genrndsymb(1,nn);
end

tree.maxsize = n;
tree.nodetyp = vt;
tree.node = vn;
tree.param = zeros(floor((tree.maxsize+1)/2),1);
tree.paramn = 0;
return

%------------------------------------------------------------------
function [nodetyp,node] = tree_genrndsymb(p0,nn)
%  随机生成操作符集和终止符集

if rand<p0,
  nodetyp = 2;
else
  nodetyp = 1;
end
node = floor(nn(nodetyp)*rand)+1;
return