This GAlib example shows how to use genetic algorithms for a binary string genome to evolve to triplets of zeroes and ones.

Download the Qt Project of 'GAlibExample1' (zip)

Operating system: Ubuntu 10.04 LTS Lucid Lynx

IDE: Qt Creator 2.0.0

Project type: Qt4 Console Application

Compiler: G++ 4.4.1

Libraries used:

Galib: version 2.4.7-3, from Ubuntu Software centre ('libga-dev')
STL: from GCC, shipped with Qt Creator 2.0.0

Qt project file


#-------------------------------------------------

#

# Project created by QtCreator 2010-07-23T11:53:46

#

#-------------------------------------------------

QT       += core

QT       -= gui

TARGET = CppGalibExample1

CONFIG   += console

CONFIG   -= app_bundle

TEMPLATE = app

LIBS += -L/usr/local/lib -lga

SOURCES += main.cpp

Source code


#include <cassert>

#include <iostream>

#include <ga/GASimpleGA.h>

#include <ga/GA2DBinStrGenome.h>



//Goal genome consist of triplets of zeroes and ones:

//000 111 000 111 etc.

float triplet_objective(GAGenome& g)

{

  const GA2DBinaryStringGenome * const genome

      = dynamic_cast<GA2DBinaryStringGenome*>(&g);

  assert(genome && "Assume a binary string genome for triplet objective");

  const int maxx = genome->width();

  const int maxy = genome->height();



  float score=0.0;



  for(int y=0; y!=maxy; y++)

  {

    for(int x=0; x!=maxx; x++)

    {

      const int goal = (x / 3) % 2;

      if(genome->gene(x,y) == goal) score+=1.0;

    }

  }

  return score;

}



int main()

{

  //Create first genome

  const int genome_length = 42;

  const int ploidy = 2; //Diploid

  const GA2DBinaryStringGenome first_genome(genome_length, ploidy, triplet_objective);



  //Set up the genetic algorithm

  GASimpleGA g(first_genome);

  g.populationSize(100);

  g.nGenerations(1000);

  g.pMutation(0.001);

  g.pCrossover(0.5);

  g.evolve();



  //Check the best genome

  const GAGenome& best_genome = g.statistics().bestIndividual();

  std::cout

      << "Best genome found:\n"

      << best_genome

      << "\n";

}

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(C++) GAlib example 1: binary triplets evolution

Qt project file

Source code