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Viewing changes to src/backend/optimizer/geqo/geqo_mutation.c

  • Committer: Bazaar Package Importer
  • Author(s): Martin Pitt
  • Date: 2009-03-20 12:00:13 UTC
  • Revision ID: james.westby@ubuntu.com-20090320120013-hogj7egc5mjncc5g
Tags: upstream-8.4~0cvs20090328
Import upstream version 8.4~0cvs20090328

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src/backend/optimizer/geqo/geqo_mutation.c
 
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/*------------------------------------------------------------------------
 
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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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* $PostgreSQL$
 
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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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void
 
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geqo_mutation(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(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(num_gene - 1, 0);
 
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                swap2 = geqo_randint(num_gene - 1, 0);
 
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                while (swap1 == swap2)
 
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                        swap2 = geqo_randint(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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}