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# FirstBitEA.cpp

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`//----------------------------------------------------------------------------- // 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; }`

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