geqo_px.c File Reference

#include "postgres.h"
#include "optimizer/geqo_random.h"
#include "optimizer/geqo_recombination.h"

Include dependency graph for geqo_px.c:

Go to the source code of this file.

Functions
void	px (PlannerInfo *root, Gene *tour1, Gene *tour2, Gene *offspring, int num_gene, City *city_table)

---

Function Documentation

void px	(	PlannerInfo *	root,
		Gene *	tour1,
		Gene *	tour2,
		Gene *	offspring,
		int	num_gene,
		City *	city_table
	)

Definition at line 46 of file geqo_px.c.

References geqo_randint, i, and City::used.

Referenced by geqo().

{

    int         num_positions;
    int         i,
                pos,
                tour2_index,
                offspring_index;

    /* initialize city table */
    for (i = 1; i <= num_gene; i++)
        city_table[i].used = 0;

    /* choose random positions that will be inherited directly from parent */
    num_positions = geqo_randint(root, 2 * num_gene / 3, num_gene / 3);

    /* choose random position */
    for (i = 0; i < num_positions; i++)
    {
        pos = geqo_randint(root, num_gene - 1, 0);

        offspring[pos] = tour1[pos];    /* transfer cities to child */
        city_table[(int) tour1[pos]].used = 1;  /* mark city used */
    }

    tour2_index = 0;
    offspring_index = 0;


    /* px main part */

    while (offspring_index < num_gene)
    {

        /* next position in offspring filled */
        if (!city_table[(int) tour1[offspring_index]].used)
        {

            /* next city in tour1 not used */
            if (!city_table[(int) tour2[tour2_index]].used)
            {

                /* inherit from tour1 */
                offspring[offspring_index] = tour2[tour2_index];

                tour2_index++;
                offspring_index++;
            }
            else
            {                   /* next city in tour2 has been used */
                tour2_index++;
            }

        }
        else
        {                       /* next position in offspring is filled */
            offspring_index++;
        }

    }

}