crossovr.c

Genetic Programing of music

/*  lil-gp Genetic Programming System, version 1.0, 11 July 1995
 *  Copyright (C) 1995  Michigan State University
 * 
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of version 2 of the GNU General Public License as
 *  published by the Free Software Foundation.
 * 
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 * 
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *  
 *  Douglas Zongker       ([e-mail])
 *  Dr. Bill Punch        ([e-mail])
 *
 *  Computer Science Department
 *  A-714 Wells Hall
 *  Michigan State University
 *  East Lansing, Michigan  48824
 *  USA
 *  
 */

#include <lilgp.h>

typedef struct
{
     int keep_trying;
     double internal;
     double external;
     double *tree;       /* probability that a given tree
			    will be selected for crossover. */
     double *treecumul;  /* running sum of "tree" field. */
     double treetotal;   /* total of all tree fields. */
     double *func;       /* probability that a given function
			    set will be selected for crossover. */
     char *sname;
     sel_context *sc;
     char *sname2;
     sel_context *sc2;
} crossover_data;

/* operator_crossver_init()
 *
 * called to parse crossover options and initialize one record
 * of a breedphase table appropriately.
 */

int operator_crossover_init ( char *options, breedphase *bp )
{
     int errors = 0;
     crossover_data *cd;
     int i, j, k, m;
     double r;
     char **argv, **targv;
     int internalset = 0, externalset = 0;
     char *cp;

     cd = (crossover_data *)MALLOC ( sizeof ( crossover_data ) );

     /* place values into the breedphase table record. */
     bp->operator = OPERATOR_CROSSOVER;
     bp->data = (void *)cd;
     bp->operator_free = operator_crossover_free;
     bp->operator_start = operator_crossover_start;
     bp->operator_end = operator_crossover_end;
     bp->operator_operate = operator_crossover;

     /* default values for all the crossover options. */
     cd->keep_trying = 0;
     cd->internal = 0.9;
     cd->external = 0.1;
     cd->tree = (double *)MALLOC ( tree_count * sizeof ( double ) );
     cd->treecumul = (double *)MALLOC ( tree_count * sizeof ( double ) );
     for ( j = 0; j < tree_count; ++j )
          cd->tree[j] = 0.0;
     cd->treetotal = 0.0;
     cd->func = (double *)MALLOC ( fset_count * sizeof ( double ) );
     cd->sname = NULL;
     cd->sname2 = NULL;

     /* break the options string into an argv-style array of strings. */
     j = parse_o_rama ( options, &argv );

     for ( i = 0; i < j; ++i )
     {
	  /* parse "keep_trying" option. */
          if ( strcmp ( "keep_trying", argv[i] ) == 0 )
          {
	       /* translate a string into a binary value.  returns -1 if
		  the string is not one of the valid strings meaning
		  yes or no. */
               cd->keep_trying = translate_binary ( argv[++i] );
               if ( cd->keep_trying == -1 )
               {
                    ++errors;
                    error ( E_ERROR, "crossover: \"%s\" is not a valid setting for \"keep_trying\".",
                           argv[i] );
               }
          }
	  /* parse "internal" option. */
          else if ( strcmp ( "internal", argv[i] ) == 0 )
          {
               internalset = 1;
               cd->internal = strtod ( argv[++i], NULL );
               if ( cd->internal < 0.0 )
               {
                    ++errors;
                    error ( E_ERROR, "crossover: \"internal\" must be nonnegative." );
               }
          }
	  /* parse "external" option. */
          else if ( strcmp ( "external", argv[i] ) == 0 )
          {
               externalset = 1;
               cd->external = strtod ( argv[++i], NULL );
               if ( cd->external < 0.0 )
               {
                    ++errors;
                    error ( E_ERROR, "crossover: \"external\" must be nonnegative." );
               }
          }
	  /* parse "select" option. */
          else if ( strcmp ( "select", argv[i] ) == 0 )
          {
               if ( !exists_select_method ( argv[++i] ) )
               {
                    ++errors;
                    error ( E_ERROR, "crossover: \"%s\" is not a known selection method.",
                           argv[i] );
               }
               FREE ( cd->sname );
               cd->sname = (char *)MALLOC ( (strlen(argv[i])+1) * sizeof ( char ) );
               strcpy ( cd->sname, argv[i] );
               if ( cd->sname2 == NULL )
                    cd->sname2 = cd->sname;
          }
	  /* parse "select2" option. */
          else if ( strcmp ( "select2", argv[i] ) == 0 )
          {
               if ( !exists_select_method ( argv[++i] ) )
               {
                    ++errors;
                    error ( E_ERROR, "crossover: \"%s\" is not a known selection method.",
                           argv[i] );
               }
               if ( cd->sname2 && cd->sname != cd->sname2 )
                    FREE ( cd->sname2 );
               cd->sname2 = (char *)MALLOC ( (strlen(argv[i])+1) * sizeof ( char ) );
               strcpy ( cd->sname2, argv[i] );
          }
	  /* parse "tree" option. */
          else if ( strcmp ( "tree", argv[i] ) == 0 )
          {
               k = parse_o_rama ( argv[++i], &targv );
               if ( k != tree_count )
               {
                    ++errors;
                    error ( E_ERROR, "crossover: wrong number of tree fields: \"%s\".",
                           argv[i] );
               }
               else
               {
                    for ( m = 0; m < k; ++m )
                    {
                         cd->tree[m] = strtod ( targv[m], &cp );
                         if ( *cp )
                         {
                              ++errors;
                              error ( E_ERROR, "crossover: \"%s\" is not a number.",
                                     targv[m] );
                         }
                    }
               }
               
               free_o_rama ( k, &targv );
          }
	  /* parse "tree#" option. */
          else if ( strncmp ( "tree", argv[i], 4 ) == 0 )
          {
               k = strtol ( argv[i]+4, &cp, 10 );
               if ( *cp )
               {
                    ++errors;
                    error ( E_ERROR, "crossover: unknown option \"%s\".",
                           argv[i] );
               }
               if ( k < 0 || k >= tree_count )
               {
                    ++errors;
                    error ( E_ERROR, "crossover: \"%s\" is out of range.",
                           argv[i] );
               }
               else
               {
                    cd->tree[k] = strtod ( argv[++i], &cp );
                    if ( *cp )
                    {
                         ++errors;
                         error ( E_ERROR, "crossover: \"%s\" is not a number.",
                                argv[i] );
                    }
               }
          }
          else
          {
               ++errors;
               error ( E_ERROR, "crossover: unknown option \"%s\".",
                      argv[i] );
          }
     }
     
     free_o_rama ( j, &argv );
     
     if ( internalset && !externalset )
          cd->external = 0.0;
     else if ( !internalset && externalset )
          cd->internal = 0.0;
     
     if ( cd->sname == NULL )
     {
          ++errors;
          error ( E_ERROR, "crossover: no selection method specified." );
     }

     /** compute "func" array from the "tree" array. **/
     
     for ( j = 0; j < tree_count; ++j )
          cd->treetotal += cd->tree[j];
     if ( cd->treetotal == 0.0 )
     {
          for ( j = 0; j < tree_count; ++j )
               cd->tree[j] = 1.0;
          cd->treetotal = tree_count;
     }
          
     for ( j = 0; j < fset_count; ++j )
          cd->func[j] = 0.0;
     for ( j = 0; j < tree_count; ++j )
          cd->func[tree_map[j].fset] += cd->tree[j];
     
     r = 0.0;
     for ( j = 0; j < fset_count; ++j )
          r = (cd->func[j] += r);

#ifdef DEBUG
     if ( !errors )
     {
          printf ( "crossover options:\n" );
          printf ( "   internal: %lf  external: %lf\n", cd->internal, cd->external );
          printf ( "   keep_trying: %d\n", cd->keep_trying );
          printf ( "   primary selection: %s\n", cd->sname==NULL?"NULL":cd->sname );
          printf ( "   second selection: %s\n", cd->sname2==NULL?"NULL":(cd->sname2==cd->sname?"same as primary":cd->sname2) );
          printf ( "   tree total: %lf\n", cd->treetotal );
          for ( j = 0; j < tree_count; ++j )
               printf ( "   tree %d: %lf\n", j, cd->tree[j] );
          for ( j = 0; j < fset_count; ++j )
               printf ( "   fset %d: %lf\n", j, cd->func[j] );
     }
#endif
     
     return errors;
}

/* operator_crossover_free()
 *
 * free the crossover-specific data structure.
 */

void operator_crossover_free ( void *data )
{
     crossover_data * cd;

     cd = (crossover_data *)data;

     FREE ( cd->sname );
     if ( cd->sname != cd->sname2 )
          FREE ( cd->sname2 );
     FREE ( cd->tree );
     FREE ( cd->treecumul );
     FREE ( cd->func );
     FREE ( cd );
}

/* operator_crossover_start()
 *
 * called at the start of the breeding process each generation.
 * initializes the selection contexts for this phase.
 */

void operator_crossover_start ( population *oldpop, void *data )
{
     crossover_data * cd;
     select_context_func_ptr select_con;

     cd = (crossover_data *)data;
     
     select_con = get_select_context ( cd->sname );
     cd->sc = select_con ( SELECT_INIT, NULL, oldpop, cd->sname );

     /* if there is a separate selection method specified for the
	second parent... */
     if ( cd->sname2 != cd->sname )
     {
	  /* ...then initialize it too. */
          select_con = get_select_context ( cd->sname2 );
          cd->sc2 = select_con ( SELECT_INIT, NULL, oldpop, cd->sname2 );
     }
     else
	  /* ...otherwise use the first context. */
          cd->sc2 = cd->sc;
}

/* operator_crossover_end()
 *
 * called when breeding is finished each generation.  frees up selection
 * contexts for this phase.
 */

void operator_crossover_end ( void *data )
{
     crossover_data * cd;

     cd = (crossover_data *)data;

     cd->sc->context_method ( SELECT_CLEAN, cd->sc, NULL, NULL );
     if ( cd->sname != cd->sname2 )