1/*------------------------------------------------------------------------
2*
3* geqo_ox1.c
4*
5* order crossover [OX] routines;
6* OX1 operator according to Davis
7* (Proc Int'l Joint Conf on AI)
8*
9* src/backend/optimizer/geqo/geqo_ox1.c
10*
11*-------------------------------------------------------------------------
12*/
13
14/* contributed by:
15 =*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
16 * Martin Utesch * Institute of Automatic Control *
17 = = University of Mining and Technology =
18 * utesch@aut.tu-freiberg.de * Freiberg, Germany *
19 =*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
20 */
21
22/* the ox algorithm is adopted from Genitor : */
23/*************************************************************/
24/* */
25/* Copyright (c) 1990 */
26/* Darrell L. Whitley */
27/* Computer Science Department */
28/* Colorado State University */
29/* */
30/* Permission is hereby granted to copy all or any part of */
31/* this program for free distribution. The author's name */
32/* and this copyright notice must be included in any copy. */
33/* */
34/*************************************************************/
35
36#include "postgres.h"
37#include "optimizer/geqo_random.h"
38#include "optimizer/geqo_recombination.h"
39
40#if defined(OX1)
41
42/* ox1
43 *
44 * position crossover
45 */
46void
47ox1(PlannerInfo *root, Gene *tour1, Gene *tour2, Gene *offspring, int num_gene,
48 City * city_table)
49{
50 int left,
51 right,
52 k,
53 p,
54 temp;
55
56 /* initialize city table */
57 for (k = 1; k <= num_gene; k++)
58 city_table[k].used = 0;
59
60 /* select portion to copy from tour1 */
61 left = geqo_randint(root, num_gene - 1, 0);
62 right = geqo_randint(root, num_gene - 1, 0);
63
64 if (left > right)
65 {
66 temp = left;
67 left = right;
68 right = temp;
69 }
70
71 /* copy portion from tour1 to offspring */
72 for (k = left; k <= right; k++)
73 {
74 offspring[k] = tour1[k];
75 city_table[(int) tour1[k]].used = 1;
76 }
77
78 k = (right + 1) % num_gene; /* index into offspring */
79 p = k; /* index into tour2 */
80
81 /* copy stuff from tour2 to offspring */
82 while (k != left)
83 {
84 if (!city_table[(int) tour2[p]].used)
85 {
86 offspring[k] = tour2[p];
87 k = (k + 1) % num_gene;
88 city_table[(int) tour2[p]].used = 1;
89 }
90 p = (p + 1) % num_gene; /* increment tour2-index */
91 }
92
93}
94
95#endif /* defined(OX1) */
96