67 lines
1.8 KiB
C
67 lines
1.8 KiB
C
/*------------------------------------------------------------------------
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*
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* geqo_mutation.c
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*
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* TSP mutation routines
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*
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* src/backend/optimizer/geqo/geqo_mutation.c
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*
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*-------------------------------------------------------------------------
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*/
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/* contributed by:
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=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
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* Martin Utesch * Institute of Automatic Control *
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= = University of Mining and Technology =
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* utesch@aut.tu-freiberg.de * Freiberg, Germany *
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=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
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*/
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/* this is adopted from Genitor : */
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/*************************************************************/
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/* */
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/* Copyright (c) 1990 */
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/* Darrell L. Whitley */
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/* Computer Science Department */
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/* Colorado State University */
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/* */
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/* Permission is hereby granted to copy all or any part of */
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/* this program for free distribution. The author's name */
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/* and this copyright notice must be included in any copy. */
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/* */
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/*************************************************************/
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#include "postgres.h"
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#include "optimizer/geqo_mutation.h"
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#include "optimizer/geqo_random.h"
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#if defined(CX) /* currently used only in CX mode */
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void
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geqo_mutation(PlannerInfo *root, Gene *tour, int num_gene)
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{
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int swap1;
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int swap2;
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int num_swaps = geqo_randint(root, num_gene / 3, 0);
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Gene temp;
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while (num_swaps > 0)
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{
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swap1 = geqo_randint(root, num_gene - 1, 0);
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swap2 = geqo_randint(root, num_gene - 1, 0);
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while (swap1 == swap2)
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swap2 = geqo_randint(root, num_gene - 1, 0);
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temp = tour[swap1];
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tour[swap1] = tour[swap2];
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tour[swap2] = temp;
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num_swaps -= 1;
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}
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}
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#endif /* defined(CX) */
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