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/*------------------------------------------------------------------------
*
* geqo_recombination.c--
* misc recombination procedures
*
* $Id: geqo_recombination.c,v 1.1 1997/02/19 12:57:42 scrappy Exp $
*
*-------------------------------------------------------------------------
*/
/* contributed by:
=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
* Martin Utesch * Institute of Automatic Control *
= = University of Mining and Technology =
* utesch@aut.tu-freiberg.de * Freiberg, Germany *
=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
*/
/* -- parts of this are adapted from D. Whitley's Genitor algorithm -- */
#include "postgres.h"
#include "nodes/pg_list.h"
#include "nodes/relation.h"
#include "nodes/primnodes.h"
#include "utils/palloc.h"
#include "utils/elog.h"
#include "optimizer/internal.h"
#include "optimizer/paths.h"
#include "optimizer/pathnode.h"
#include "optimizer/clauses.h"
#include "optimizer/cost.h"
#include "optimizer/geqo_gene.h"
#include "optimizer/geqo.h"
#include "optimizer/geqo_recombination.h"
#include "optimizer/geqo_random.h"
/*
* init_tour--
*
* Randomly generates a legal "traveling salesman" tour
* (i.e. where each point is visited only once.)
* Essentially, this routine fills an array with all possible
* points on the tour and randomly chooses the 'next' city from
* this array. When a city is chosen, the array is shortened
* and the procedure repeated.
*
*/
void
init_tour(Gene *tour, int num_gene)
{
Gene *tmp;
int remainder;
int next, i;
tmp = (Gene *) palloc (num_gene*sizeof(Gene));
for(i = 0; i < num_gene; i++) {
tmp[i] = (Gene) i+1; /* builds tours "1 - 2 - 3" etc. */
}
remainder = num_gene - 1;
for(i = 0; i < num_gene; i++) {
next = (int) geqo_randint(remainder, 0); /* choose city between 0 and remainder */
tour[i] = tmp[next];
tmp[next] = tmp[remainder];
remainder--;
}
pfree(tmp);
}
/* alloc_city_table--
*
* allocate memory for city table
*
*/
City *
alloc_city_table(int num_gene)
{
City *city_table;
/* palloc one extra location so that nodes numbered
1..n can be indexed directly; 0 will not be used */
city_table = (City *) palloc ((num_gene+1)*sizeof(City));
return (city_table);
}
/* free_city_table--
*
* deallocate memory of city table
*
*/
void
free_city_table(City *city_table)
{
pfree(city_table);
}
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