ex25.cpp

这是一个面向对象的GA遗传算法库GAlib: A C++ Library of Genetic Algorithm Components)

/* ----------------------------------------------------------------------------
  ex25.C
  mbwall jan96
  Copyright (c) 1995-1996  Massachusetts Institute of Technology

 DESCRIPTION:
   This example shows how to do multiple populations on a single CPU.
---------------------------------------------------------------------------- */
#include <stdio.h>
#include <ga/GA1DBinStrGenome.h>
#include <ga/GADemeGA.h>
#include <ga/std_stream.h>

#define cout STD_COUT
#define endl STD_ENDL

float Objective(GAGenome &);

int
main(int argc, char** argv) {
  cout << "Example 25\n\n";
  cout << "This example uses a genetic algorithm with multiple populations.\n";
  cout << endl;

// See if we've been given a seed to use (for testing purposes).  When you
// specify a random seed, the evolution will be exactly the same each time
// you use that seed number.

  unsigned int seed = 0;
  for(int ii=1; ii<argc; ii++) {
    if(strcmp(argv[ii++],"seed") == 0) {
      seed = atoi(argv[ii]);
    }
  }

  GA1DBinaryStringGenome genome(32, Objective);
  GADemeGA ga(genome);
  ga.nPopulations(5);
  ga.populationSize(30);
  ga.nGenerations(100);
  ga.pMutation(0.03);
  ga.pCrossover(1.0);
  ga.parameters(argc, argv);
  cout << "initializing..."; cout.flush();
  ga.initialize(seed);
  cout << "evolving..."; cout.flush();
  while(!ga.done()) {
    ga.step();
    cout << "."; cout.flush();
  }
  cout << endl;

  cout << "best individual is: " << ga.statistics().bestIndividual() << "\n";
  cout << "\n" << ga.statistics() << "\n";  

  return 0;
}

// This is the 1-max objective function - try to maximize the number of 1s in 
// a bit string of arbitrary length.
float
Objective(GAGenome& g) {
  GA1DBinaryStringGenome & genome = (GA1DBinaryStringGenome &)g;
  float score=0.0;
  for(int i=0; i<genome.length(); i++)
    score += genome.gene(i);
  score /= genome.length();
  return score;
}