ex14.cpp

这是一个面向对象的GA遗传算法库GAlib: A C++ Library of Genetic Algorithm Components)

/* ----------------------------------------------------------------------------
  ex14.C
  mbwall 29apr95
  Copyright (c) 1995-1996  Massachusetts Institute of Technology

 DESCRIPTION:
   Example program for a composite genome derived from the GAGenome and
containing a list of lists.  This example shows how to derive your own genome
class and illustrates the use of one of the template genomes (GAListGenome) 
from the GAlib.
---------------------------------------------------------------------------- */
#include <stdio.h>
#include <stdlib.h>
#include <ga/ga.h>
#include <ga/std_stream.h>

#define cout STD_COUT
#define cerr STD_CERR
#define endl STD_ENDL
#define istream STD_ISTREAM
#define ostream STD_OSTREAM


// Here we specify how big the lists will be and how many lists will be in each
// composite genome.  These are the default values - you can change them from
// the command line.  Beware that this program will break if nrobots is bigger
// than the size of the lists.
int listsize = 10;
int nrobots = 6;


// This is the class definition.  We override the methods of the base class and
// define a few methods of our own to access the protected members.  The list
// genomes in the composite genome are assigned the 'List' operators
// by default (they can be overridden by using the 'Operator' members on the
// lists explicitly).
//   The ID can be any number over 200 (IDs under 200 are reserved for use by
// GAlib objects).
class RobotPathGenome : public GAGenome {
public:
  GADefineIdentity("RobotPathGenome", 251);
  static void Initializer(GAGenome&);
  static int Mutator(GAGenome&, float);
  static float Comparator(const GAGenome&, const GAGenome&);
  static float Evaluator(GAGenome&);
  static void PathInitializer(GAGenome&);
  static int Crossover(const GAGenome&, const GAGenome&, GAGenome*, GAGenome*);
public:
  RobotPathGenome(int nrobots, int pathlength);
  RobotPathGenome(const RobotPathGenome & orig) { n=l=0; list=0; copy(orig); }
  RobotPathGenome operator=(const GAGenome & arg) { copy(arg); return *this; }
  virtual ~RobotPathGenome();
  virtual GAGenome *clone(GAGenome::CloneMethod) const ;
  virtual void copy(const GAGenome & c);
  virtual int equal(const GAGenome& g) const;
  virtual int read(istream & is);
  virtual int write(ostream & os) const ;

  GAListGenome<int> & path(const int i){return *list[i];}
  int npaths() const { return n; }
  int length() const { return l; }

protected:
  int n, l;
  GAListGenome<int> **list;
};




RobotPathGenome::RobotPathGenome(int nrobots, int pathlength) :
GAGenome(Initializer, Mutator, Comparator){
  evaluator(Evaluator); crossover(Crossover); n = nrobots; l = pathlength;
  list = (n ? new GAListGenome<int> * [n] : (GAListGenome<int> **)0);
  for(int i=0; i<n; i++){
    list[i] = new GAListGenome<int>;
    list[i]->initializer(PathInitializer);
    list[i]->mutator(GAListGenome<int>::SwapMutator);
  }
}

void
RobotPathGenome::copy(const GAGenome& g) {
  if(&g != this && sameClass(g)){
    GAGenome::copy(g);		// copy the base class part
    RobotPathGenome & genome = (RobotPathGenome &)g;
    if(n == genome.n){
      for(int i=0; i<n; i++)
	list[i]->copy(*genome.list[i]);
    }
    else{
      int i;
      for(i=0; i<n; i++)
	delete list[i];
      delete [] list;
      n = genome.n;
      list = new GAListGenome<int> * [n];
      for(i=0; i<n; i++)
	list[i] = (GAListGenome<int> *)genome.list[i]->clone();
    }
  }
}

RobotPathGenome::~RobotPathGenome(){
  for(int i=0; i<n; i++)
    delete list[i];
  delete [] list;
}

GAGenome*
RobotPathGenome::clone(GAGenome::CloneMethod) const {
  return new RobotPathGenome(*this); 
}

int 
RobotPathGenome::equal(const GAGenome& g) const {
  RobotPathGenome& genome = (RobotPathGenome&)g;
  int flag=0;
  for(int i=0; i<n && flag==0; i++)
    flag = list[i]->equal(*genome.list[i]);
  return flag;
}

int 
RobotPathGenome::read(istream & is) {
  for(int i=0; i<n; i++)
    is >> *(list[i]);
  return is.fail() ? 1 : 0;
}

int 
RobotPathGenome::write(ostream & os) const {
  for(int i=0; i<n; i++)
    os << "list " << i << ":\t" << *(list[i]) << "\n";
  return os.fail() ? 1 : 0;
}




// These are the definitions of the operators for the robot path genome.
void 
RobotPathGenome::Initializer(GAGenome& g) {
  RobotPathGenome & genome = (RobotPathGenome &)g;
  for(int i=0; i<genome.npaths(); i++)
    genome.path(i).initialize();
  genome._evaluated = gaFalse;
}

int 
RobotPathGenome::Mutator(GAGenome& g, float pmut) {
  RobotPathGenome & genome = (RobotPathGenome &)g;
  int nMut = 0;
  for(int i=0; i<genome.npaths(); i++)
    nMut += genome.path(i).mutate(pmut);
  if(nMut) genome._evaluated = gaFalse;
  return nMut;
}

float
RobotPathGenome::Comparator(const GAGenome& a, const GAGenome& b) {
  RobotPathGenome& sis = (RobotPathGenome &)a;
  RobotPathGenome& bro = (RobotPathGenome &)b;
  float diff = 0;
  for(int i=0; i<sis.npaths(); i++)
    diff += sis.path(i).compare(bro.path(i));
  return diff/sis.npaths();
}

// The objective function should evaluate the genomes.  This one tries to
// put the node with value 0 into the nth position where n is the number of the
// list in the composite genome.  We're assuming that there are more nodes
// in the list than there are lists in the composite genome.
float
RobotPathGenome::Evaluator(GAGenome & c) {
  RobotPathGenome & genome = (RobotPathGenome &)c;
  float score=0;
  for(int i=0; i<genome.npaths(); i++)
    if(*genome.path(i).warp(i) == 0) score += 1;
  return score;
}


// This crossover method assumes that all of the robot path genomes have the 
// same number of paths in them.  With a few modifications you could make the
// paths be variable length, but then you must use a crossover method other
// than the partial match crossover used here (defined in the robot path
// crossover object).
int
RobotPathGenome::
Crossover(const GAGenome& a, const GAGenome& b, GAGenome* c, GAGenome* d) {
  RobotPathGenome& mom = (RobotPathGenome &)a;
  RobotPathGenome& dad = (RobotPathGenome &)b;

  int n=0;
  if(c && d){
    RobotPathGenome& sis = (RobotPathGenome &)*c;
    RobotPathGenome& bro = (RobotPathGenome &)*d;
    for(int i=0; i<mom.npaths(); i++)
      GAListGenome<int>::PartialMatchCrossover(mom.path(i), dad.path(i),
					       &sis.path(i), &bro.path(i));
    sis._evaluated = gaFalse;
    bro._evaluated = gaFalse;
    n=2;
  }
  else if(c) {
    RobotPathGenome& sis = (RobotPathGenome &)*c;
    for(int i=0; i<mom.npaths(); i++)
      GAListGenome<int>::PartialMatchCrossover(mom.path(i), dad.path(i),
					       &sis.path(i), 0);
    sis._evaluated = gaFalse;
    n=1;
  }
  else if(d) {
    RobotPathGenome& bro = (RobotPathGenome &)*d;
    for(int i=0; i<mom.npaths(); i++)
      GAListGenome<int>::PartialMatchCrossover(mom.path(i), dad.path(i),
					       0, &bro.path(i));
    bro._evaluated = gaFalse;
    n=1;
  }
  return n;
}


// This is the initialization operator for our lists.  We create a list that is
// n long and whose nodes contain numbers in sequence.
//   The first thing to do in the initializer is to clear out any old 
// contents - we do not want to build our new list on a previously existing
// one!  Notice that we have to cast the genome into the type of 
// genome we're using (in this case a list).  The GA always operates on
// generic genomes.
//   All of our lists must be the same length since we're going to use the
// ordered crossover operators.
void 
RobotPathGenome::PathInitializer(GAGenome & c){
  GAListGenome<int> & list = (GAListGenome<int> &)c;

// We must first destroy any pre-existing list.
  while(list.head()) list.destroy();

// Insert the head of the list.  This node has a random number in it, but the
// number is in a range different than those in the rest of the list.  This
// way we'll be able to see how the lists get scrambled up.  Since we're using
// ordered crossover (see the header file) we should never end up with more 
// than one node in each list that has a given value.
  list.insert(0, GAListBASE::HEAD);

// Loop through n times and append nodes onto the end of the list.
  int i;
  for(i=0; i<listsize-1; i++)
    list.insert(i+20, GAListBASE::AFTER);

// Now randomize the contents of the list.
  for(i=0; i<listsize; i++)
    if(GARandomBit()) list.swap(i, GARandomInt(0, listsize-1));
}



// Here is the specialization of the write method for our lists.  The default 
// write method just prints out pointers to the contents of the nodes (it has
// no way of knowing in advance how you'll want things printed).  Here we 
// do almost the same thing, but print out the contents of the nodes rather
// than the pointers to the contents.
template <> int
GAListGenome<int>::write(ostream & os) const {
  int *cur, *head;
  GAListIter<int> iter(*this);
  if((head=iter.head()) != 0) os << *head << " ";
  for(cur=iter.next(); cur && cur != head; cur=iter.next())
    os << *cur << " ";
  return os.fail() ? 1 : 0;
}














int
main(int argc, char *argv[])
{
  cout << "Example 14\n\n";
  cout << "This example shows how to create a genome that contains\n";
  cout << "a list of lists.  We create a composite genome that has\n";
  cout << "lists in it.  Each list has some nodes, only one of which\n";
  cout << "contains the number 0.  The objective is to move the node with\n";
  cout << "number 0 in it to the nth position where n is the number of the\n";
  cout << "list within the composite genome.\n\n";
  cout.flush();

// See if we've been given a seed to use (for testing purposes).  When you
// specify a random seed, the evolution will be exactly the same each time
// you use that seed number.

  int i;

  for(i=1; i<argc; i++){
    if(strcmp("nr", argv[i]) == 0){
      if(++i >= argc){
        cerr << argv[0] << ": number of robots needs a value.\n";
        exit(1);
      }
      else{
	nrobots = atoi(argv[i]);
        continue;
      }
    }
    else if(strcmp("pl", argv[i]) == 0){
      if(++i >= argc){
        cerr << argv[0] << ": path length needs a value.\n";
        exit(1);
      }
      else{
	listsize = atoi(argv[i]);
        continue;
      }
    }
    else if(strcmp(argv[i],"seed") == 0) {
      if(++i >= argc){
        cerr << argv[0] << ": seed needs a value.\n";
        exit(1);
      }
      else {
	GARandomSeed((unsigned int)atoi(argv[i]));
      }
    }
    else if(strcmp("help",argv[i]) == 0){
      cerr << "valid arguements include standard GAlib arguments plus:\n";
      cerr << "  nr\tnumber of robots (" << nrobots << ")\n";
      cerr << "  pl\tlength of the paths (" << listsize << ")\n";
      cerr << "\n";
      exit(1);
    }
  }

  if(listsize < nrobots) {
    cerr << "path length must be greater than the number of robots.\n";
    exit(1);
  }

  RobotPathGenome genome(nrobots, listsize);
  GASteadyStateGA ga(genome);
  ga.parameters(argc,argv);
  ga.evolve();

  genome.initialize();
  cout << "a randomly-generated set of paths:\n" << genome << endl;
  cout << "the ga generated:\n" << ga.statistics().bestIndividual() << "\n";

  return 0;
}



// force instantiations for compilers that do not do auto instantiation.
// for some compilers (e.g. metrowerks) this must come after any
// specializations or you will get 'multiply-defined errors when you compile.
#if !defined(GALIB_USE_AUTO_INST)
#include <ga/GAList.C>
#include <ga/GAListGenome.C>
GALIB_INSTANTIATION_PREFIX GAList<int>;
GALIB_INSTANTIATION_PREFIX GAListGenome<int>;
#endif