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