geqo_ox2.c File Reference

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

Include dependency graph for geqo_ox2.c:

Go to the source code of this file.

Functions
void	ox2 (PlannerInfo *root, Gene *tour1, Gene *tour2, Gene *offspring, int num_gene, City *city_table)

---

Function Documentation

void ox2	(	PlannerInfo *	root,
		Gene *	tour1,
		Gene *	tour2,
		Gene *	offspring,
		int	num_gene,
		City *	city_table
	)

Definition at line 46 of file geqo_ox2.c.

References geqo_randint, City::select_list, and City::used.

Referenced by geqo().

{
    int         k,
                j,
                count,
                pos,
                select,
                num_positions;

    /* initialize city table */
    for (k = 1; k <= num_gene; k++)
    {
        city_table[k].used = 0;
        city_table[k - 1].select_list = -1;
    }

    /* determine the number of positions to be inherited from tour1  */
    num_positions = geqo_randint(root, 2 * num_gene / 3, num_gene / 3);

    /* make a list of selected cities */
    for (k = 0; k < num_positions; k++)
    {
        pos = geqo_randint(root, num_gene - 1, 0);
        city_table[pos].select_list = (int) tour1[pos];
        city_table[(int) tour1[pos]].used = 1;  /* mark used */
    }


    count = 0;
    k = 0;

    /* consolidate the select list to adjacent positions */
    while (count < num_positions)
    {
        if (city_table[k].select_list == -1)
        {
            j = k + 1;
            while ((city_table[j].select_list == -1) && (j < num_gene))
                j++;

            city_table[k].select_list = city_table[j].select_list;
            city_table[j].select_list = -1;
            count++;
        }
        else
            count++;
        k++;
    }

    select = 0;

    for (k = 0; k < num_gene; k++)
    {
        if (city_table[(int) tour2[k]].used)
        {
            offspring[k] = (Gene) city_table[select].select_list;
            select++;           /* next city in  the select list   */
        }
        else
            /* city isn't used yet, so inherit from tour2 */
            offspring[k] = tour2[k];
    }

}