//----------------------------------------------------------------------------- -
#include -<stdexcept > // runtime_error -
//-----------------------------------------------------------------------------
-
// FirstRealGA.cpp
-
//-----------------------------------------------------------------------------
-
//*
-
// An instance of a
-VERY simple Real-coded Genetic Algorithm
-
//
-
//-----------------------------------------------------------------------------
-
// standard includes
-
#include
-<iostream>// cout
-
#include
-<strstream>// ostrstream, istrstream
-
// the general include -for eo -
#include -<eo> -
// specific incluse,
-as Real is not (yet) in the standard eo source dir
-
#include
-"eoeal.h"
-
#include
-"eoRealOp.h"
-
//-----------------------------------------------------------------------------
-
// define your individual:
-
typedef -eoReal<double> Indi; -
You say here that you will be handling arrays
-of doubles, whose fitness is a double
-
Note that this makes Indi derive from STL
-class vector<double>
-
//-----------------------------------------------------------------------------
-
/** a simple fitness
-function that computes the euclidian norm of a real vector
-
@param
-_indi A real-valued individual
-
*/
-
double
-real_value(const Indi & _indi)
-
{
-
-double sum = 0;
-
-for (unsigned i = 0; i < _indi.size(); i++)
-
-sum += _indi[i]*_indi[i];
-
-return (-sum); // maximizing
-
}
-
This simple function computes the sum of the squares of the variables
-(remember Indi is here a vector of doubles)
-
//-----------------------------------------------------------------------------
-
void
-main_function(int argc, char **argv)
-
{
-
const
-unsigned int SEED = 42;// seed for random number generator
-
const
-unsigned int VEC_SIZE = 8; // Number of object variables in genotypes
-
const
-unsigned int POP_SIZE = 20; // Size of population
-
const
-unsigned int T_SIZE = 3; // size for tournament selection
-
const
-unsigned int MAX_GEN = 500; // Maximum number of generation before STOP
-
const
-float CROSS_RATE = 0.8; // Crossover rate
-
const
-double EPSILON = 0.01; // range for real uniform mutation
-
const
-float MUT_RATE = 0.5; // 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( real_value );
-
This encapsulate the C++ function real_value into a functor -object -
////////////////////////////////
-
// Initilisation of
-population
-
////////////////////////////////
-
// declare the population
-
eoPop<Indi>
-pop;
-
Declares a population -object, which is basically an STL -vector<Indi> -
// fill it!
-
for
-(unsigned int igeno=0; igeno<POP_SIZE; igeno++)
-
-{
-
-Indi v; // generate a random individual
-
-for (unsigned ivar=0; ivar<VEC_SIZE; ivar++)
-
-{
-
-double r = 2*rng.uniform() - 1; // new value, random in [-1,1)
-
-v.push_back(r); //
-
-}
-
-eval(v); // evaluate it
-
-pop.push_back(v); // and put it in the population
-
-}
-
This initialization of the population is straightforward
-
rng.uniform() generates a double uniformly
-in [0,1),
-
v.push_back simply appends its argument
-at the end of STL vector v
-
eval(v)evaluates individal v
-the functor way, calling eval.operator()(v)
-
// sort pop before printing
-it!
-
pop.sort();
-
// Print (sorted) intial
-population (raw printout)
-
cout
-<< "Initial Population" << endl;
-
cout
-<< pop;
-
If you looked at eoPop -inheritance diagram, you noticed that it derives from eoPrintable: -hence you can stream them using the << operator. Of course, Indis -are EO objects -, which also are eoPrintable, and the << operator for eoPop -uses the << operator for Indi. -
/////////////////////////////////////
-
//
-selection and replacement
-
////////////////////////////////////
-
// The well-known roulette
-selection
-
//
-The robust tournament selection
-
eoDetTournament<Indi>
-select(T_SIZE); // SIZE in [2,POP_SIZE]
-
//
-eoSGA uses generational replacement by default
-
// so no replacement
-procedure has to be given
-
//////////////////////////////////////
-
// termination condition
-
/////////////////////////////////////
-
// stop after MAX_GEN
-generations
-
eoGenContinue<Indi>
-continuator(MAX_GEN);
-
This class is called eoGenContinue -because the main loop of all eoAlgo -says ... while continuator(pop) -
//////////////////////////////////////
-
//
-The variation operators
-
//////////////////////////////////////
-
//
-offspring(i) uniformly chosen in [parent(i)-epsilon, parent(i)+epsilon]
-
eoUniformMutation<Indi>
-mutation(EPSILON);
-
//
-offspring(i) is a linear combination of parent(i)
-
eoArithmeticCrossover<Indi>
-xover;
-
The variation operators are respectively -an eoMonOp -(unary operator) and an eoQuadOp -(binary operator that modifies both its arguments). -
/////////////////////////////////////////
-
// the algorithm
-
////////////////////////////////////////
-
// standard Generational
-GA requires
-
// 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);
-
This simple algorithm of class eoSGA is a functor -object, and running the algorithm amounts to call the operator() -on the initial population! -
// Print (sorted) intial
-population (raw printout)
-
pop.sort();
-
cout
-<< "FINAL Population\n" << pop << endl;
-
that's it - just print the final population and you're done!!! -
} -
//
-A main that catches the exceptions - do not modify!
-
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;
-
}
-
-