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Code for FirstBitGA

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//-----------------------------------------------------------------------------
// FirstBitGA.cpp
//-----------------------------------------------------------------------------
//*
// An instance of a VERY simple Bitstring Genetic Algorithm
//
//-----------------------------------------------------------------------------
// standard includes
#include <stdexcept> // runtime_error
#include <iostream> // cout
#include <strstream> // ostrstream, istrstream
// the general include for eo
#include <eo>

#include <ga.h>
//-----------------------------------------------------------------------------
// define your individuals
typedef eoBit<double> Indi; // A bitstring with fitness double

//-----------------------------------------------------------------------------
// a simple fitness function that computes the number of ones of a bitstring
// @param _indi A biststring individual
double binary_value(const Indi & _indi)
{
double sum = 0;
for (unsigned i = 0; i < _indi.size(); i++)
sum += _indi[i];
return sum;
}

//-----------------------------------------------------------------------------
void main_function(int argc, char **argv)
{

// all parameters are hard-coded!
const unsigned int SEED = 42;          // seed for random number generator
const unsigned int T_SIZE = 3;        // size for tournament selection
const unsigned int VEC_SIZE = 8;    // Number of bits in genotypes
const unsigned int POP_SIZE = 20; // Size of population
const unsigned int MAX_GEN = 100; // Maximum number of generation before STOP
const float CROSS_RATE = 0.8;          // Crossover rate
const double P_MUT_PER_BIT = 0.01; // probability of bit-flip mutation
const float MUT_RATE = 1.0;              // mutation rate

//////////////////////////
// Random seed
//////////////////////////
//reproducible random seed: if you don't change SEED above,
// you'll aways get the same result, NOT a random run
rng.reseed(SEED);

/////////////////////////////
// Fitness function
////////////////////////////
// Evaluation: from a plain C++ fn to an EvalFunc Object
eoEvalFuncPtr<Indi> eval( binary_value );

////////////////////////////////
// Initilisation of population
////////////////////////////////
// declare the population
eoPop<Indi> pop;
// fill it!
for (unsigned int igeno=0; igeno<POP_SIZE; igeno++)
     {
         Indi v;                    // void individual, to be filled
         for (unsigned ivar=0; ivar<VEC_SIZE; ivar++)
             {
                 bool r = rng.flip(); // new value, random in {0,1}
                 v.push_back(r);          // append that random value to v
             }
         eval(v);                                // evaluate it
         pop.push_back(v);             // and put it in the population
     }

// sort pop before printing it!
pop.sort();
// Print (sorted) intial population (raw printout)
cout << "Initial Population" << endl;
cout << pop;

/////////////////////////////////////
// selection and replacement
////////////////////////////////////

// The robust tournament selection
eoDetTournamentSelect<Indi> select(T_SIZE); // T_SIZE in [2,POP_SIZE]

// The simple GA evolution engine uses generational replacement
// so no replacement procedure is needed

//////////////////////////////////////
// The variation operators
//////////////////////////////////////

// 1-point crossover for bitstring
eo1PtBitXover<Indi> xover;

// standard bit-flip mutation for bitstring
eoBitMutation<Indi> mutation(P_MUT_PER_BIT);

//////////////////////////////////////
// termination condition
/////////////////////////////////////
// stop after MAX_GEN generations
eoGenContinue<Indi> continuator(MAX_GEN);

/////////////////////////////////////////
// the algorithm
////////////////////////////////////////
// standard Generational GA requires as parameters
// selection, evaluation, crossover and mutation, stopping criterion

eoSGA<Indi> gga(select, xover, CROSS_RATE, mutation, MUT_RATE,
eval, continuator);
// Apply algo to pop - that's it!
gga(pop);

// Print (sorted) intial population
pop.sort();
cout << "FINAL Population\n" << pop << endl;

}
// A main that catches the exceptions
int main(int argc, char **argv)
{
#ifdef _MSC_VER
// rng.reseed(42);
     int flag = _CrtSetDbgFlag(_CRTDBG_LEAK_CHECK_DF);
       flag |= _CRTDBG_LEAK_CHECK_DF;
     _CrtSetDbgFlag(flag);
//    _CrtSetBreakAlloc(100);
#endif
     try
     {
             main_function(argc, argv);
     }
     catch(exception& e)
     {
             cout << "Exception: " << e.what() << '\n';
     }
     return 1;
}

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Marc Schoenauer

Last modified: Sun Nov 19 08:31:26 2000