Back to Lesson 2 - Tutorial main page - Algorithm-Based - Component-Based page - Programming hints - EO documentation

FirstBitEA.cpp

Click on the figure to see the corresponding code.
In the code, the colors are meaningfull
The actual code is in boldface and the comment in normal face.

 
//-----------------------------------------------------------------------------
// FirstBitEA.cpp
//-----------------------------------------------------------------------------
//*
// Still an instance of a VERY simple Bitstring Genetic Algorithm
// (see FirstBitGA.cpp) but now with  Breeder - and Combined Ops
//
//-----------------------------------------------------------------------------
// 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
// Now in a separate file, and declared as binary_value(const vector<bool> &)
#include "binary_value.h"
//-----------------------------------------------------------------------------
void main_function(int argc, char **argv)
{
 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 = 500; // 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
 // some parameters for chosing among different operators
 const double onePointRate = 0.5;        // rate for 1-pt Xover
 const double twoPointsRate = 0.5;        // rate for 2-pt Xover
 const double URate = 0.5;                      // rate for Uniform Xover
 const double bitFlipRate = 0.5;          // rate for bit-flip mutation
 const double oneBitRate = 0.5;            // rate for one-bit mutation
 //////////////////////////
 //  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
 // you need to give the full description of the function
 eoEvalFuncPtr<Indi, double, const vector<bool>& > eval(  binary_value );
 ////////////////////////////////
 // Initilisation of population
 ////////////////////////////////
 // based on eoUniformGenerator class (see utils/eoRndGenerators.h)
 eoUniformGenerator<bool> uGen;
 eoInitFixedLength<Indi> random(VEC_SIZE, uGen);
 // Initialization of the population
 eoPop<Indi> pop(POP_SIZE, random);
 // and evaluate it in one line
 apply<Indi>(eval, pop); // STL syntax
 // 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> selectOne(T_SIZE);            // T_SIZE in [2,POP_SIZE]
 // is now encapsulated in a eoSelectPerc (entage)
 eoSelectPerc<Indi> select(selectOne);// by default rate==1
 // And we now have the full slection/replacement - though with
 // no replacement (== generational replacement) at the moment :-)
 eoNoReplacement<Indi> replace;
 //////////////////////////////////////
 // The variation operators
 //////////////////////////////////////
 // 1-point crossover for bitstring
 eo1PtBitXover<Indi> xover1;
 // uniform crossover for bitstring
 eoUBitXover<Indi> xoverU;
 // 2-pots xover
 eoNPtsBitXover<Indi> xover2(2);
 // Combine them with relative rates
 eoPropCombinedQuadOp<Indi> xover(xover1, onePointRate);
 xover.add(xoverU, URate);
 xover.add(xover2, twoPointsRate, true);
 
 // standard bit-flip mutation for bitstring
 eoBitMutation<Indi>  mutationBitFlip(P_MUT_PER_BIT);
 // mutate exactly 1 bit per individual
 eoDetBitFlip<Indi> mutationOneBit;
 // Combine them with relative rates
 eoPropCombinedMonOp<Indi> mutation(mutationBitFlip, bitFlipRate);
 mutation.add(mutationOneBit, oneBitRate, true);
 
 // The operators are  encapsulated into an eoTRansform object
 eoSGATransform<Indi> transform(xover, CROSS_RATE, mutation, MUT_RATE);
 //////////////////////////////////////
 // termination conditions: use more than one
 /////////////////////////////////////
 // stop after MAX_GEN generations
 eoGenContinue<Indi> genCont(MAX_GEN);
 // do MIN_GEN gen., then stop after STEADY_GEN gen. without improvement
 eoSteadyFitContinue<Indi> steadyCont(MIN_GEN, STEADY_GEN);
 // stop when fitness reaches a target (here VEC_SIZE)
 eoFitContinue<Indi> fitCont(0);
 // do stop when one of the above says so
 eoCombinedContinue<Indi> continuator(genCont);
 continuator.add(steadyCont);
 continuator.add(fitCont);
 /////////////////////////////////////////
 // the algorithm
 ////////////////////////////////////////
 // Easy EA requires
 // selection, transformation, eval, replacement, and stopping criterion
 eoEasyEA<Indi> gga(continuator, eval, select, transform, replace);
 // 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;
}

Back to Lesson 2 - Tutorial main page - Algorithm-Based - Component-Based page - Programming hints - EO documentation
Marc Schoenauer

Last modified: Sun Nov 19 22:26:27 2000