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/*------------------------------------------------------------------------
*
* geqo_mutation.c--
*
*    TSP mutation routines
*
* $Id: geqo_mutation.c,v 1.1 1997/02/19 12:57:13 scrappy Exp $
*
*-------------------------------------------------------------------------
*/

/* contributed by:
   =*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
   *  Martin Utesch              * Institute of Automatic Control      *
   =                             = University of Mining and Technology =
   *  utesch@aut.tu-freiberg.de  * Freiberg, Germany                   *
   =*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
 */

/* this is adopted from Genitor : */
/*************************************************************/
/*                                                           */
/*  Copyright (c) 1990                                       */
/*  Darrell L. Whitley                                       */
/*  Computer Science Department                              */
/*  Colorado State University                                */
/*                                                           */
/*  Permission is hereby granted to copy all or any part of  */
/*  this program for free distribution.   The author's name  */
/*  and this copyright notice must be included in any copy.  */
/*                                                           */
/*************************************************************/

#include "postgres.h"

#include "nodes/pg_list.h"
#include "nodes/relation.h"
#include "nodes/primnodes.h"

#include "utils/palloc.h"
#include "utils/elog.h"

#include "optimizer/internal.h"
#include "optimizer/paths.h"
#include "optimizer/pathnode.h"
#include "optimizer/clauses.h"
#include "optimizer/cost.h"

#include "optimizer/geqo_gene.h"
#include "optimizer/geqo_random.h"
#include "optimizer/geqo_mutation.h"

 void
 geqo_mutation (Gene *tour, int num_gene)
 {
     int   swap1;
     int   swap2;
     int   num_swaps = geqo_randint (num_gene/3, 0);
     Gene  temp;


     while (num_swaps > 0) {
	swap1 = geqo_randint (num_gene-1, 0);
	swap2 = geqo_randint (num_gene-1, 0);

	while (swap1 == swap2)
	   swap2 = geqo_randint (num_gene-1, 0);

	temp = tour[swap1];
	tour[swap1] = tour[swap2];
	tour[swap2] = temp;


	num_swaps -= 1;
    	}
}