global target;
target = split("METHINKS IT IS LIKE A WEASEL", "");
charset = ["A":"Z", " "];
p = ones(length(charset), 1) ./ length(charset);
parent = discrete_rnd(charset, p, length(target), 1);
mutaterate = 0.1;

C = 1000;

function r = fitness(parent, target)
  r = sum(parent == target) ./ length(target);
endfunction

function r = mutate(parent, mutaterate, charset)
  r = parent;
  p = unifrnd(0, 1, length(parent), 1);
  nmutants = sum( p < mutaterate );
  if (nmutants)
    s = discrete_rnd(charset, ones(length(charset), 1) ./ length(charset),nmutants,1);
    r( p < mutaterate ) = s;
  endif
endfunction

function r = evolve(parent, mutatefunc, fitnessfunc, C, mutaterate, charset)
  global target;
  children = [];
  for i = 1:C
    children = [children, mutatefunc(parent, mutaterate, charset)];
  endfor
  children = [parent, children];
  fitval = [];
  for i = 1:columns(children)
    fitval = [fitval, fitnessfunc(children(:,i), target)];
  endfor
  [m, im] = max(fitval);
  r = children(:, im);
endfunction

function printgen(p, t, i)
  printf("%3d %5.2f %s\n", i, fitness(p, t), p');
endfunction

i = 0;

while( !all(parent == target) )
  i++;
  parent = evolve(parent, @mutate, @fitness, C, mutaterate, charset);
  if ( mod(i, 1) == 0 )
    printgen(parent, target, i);
  endif
endwhile
disp(parent');