diff options
Diffstat (limited to 'src/backend/optimizer/geqo/geqo_selection.c')
| -rw-r--r-- | src/backend/optimizer/geqo/geqo_selection.c | 88 |
1 files changed, 45 insertions, 43 deletions
diff --git a/src/backend/optimizer/geqo/geqo_selection.c b/src/backend/optimizer/geqo/geqo_selection.c index 0c6502003bd..820de485fe4 100644 --- a/src/backend/optimizer/geqo/geqo_selection.c +++ b/src/backend/optimizer/geqo/geqo_selection.c @@ -1,36 +1,36 @@ /*------------------------------------------------------------------------- * * geqo_selection.c-- - * linear selection scheme for the genetic query optimizer + * linear selection scheme for the genetic query optimizer * * Copyright (c) 1994, Regents of the University of California * - * $Id: geqo_selection.c,v 1.1 1997/02/19 12:57:46 scrappy Exp $ + * $Id: geqo_selection.c,v 1.2 1997/09/07 04:43:24 momjian Exp $ * *------------------------------------------------------------------------- */ /* contributed by: =*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*= - * Martin Utesch * Institute of Automatic Control * - = = University of Mining and Technology = - * utesch@aut.tu-freiberg.de * Freiberg, Germany * + * Martin Utesch * Institute of Automatic Control * + = = University of Mining and Technology = + * utesch@aut.tu-freiberg.de * Freiberg, Germany * =*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*= */ /* this is adopted from D. Whitley's Genitor algorithm */ /*************************************************************/ -/* */ -/* 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. */ -/* */ +/* */ +/* 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 <math.h> @@ -55,49 +55,51 @@ #include "optimizer/geqo_copy.h" #include "optimizer/geqo_random.h" -static int linear(int max, double bias); +static int linear(int max, double bias); /* geqo_selection-- * - * according to bias described by input parameters, - * second genes are selected from the pool + * according to bias described by input parameters, + * second genes are selected from the pool */ void -geqo_selection (Chromosome *momma, Chromosome *daddy, Pool *pool, double bias) +geqo_selection(Chromosome * momma, Chromosome * daddy, Pool * pool, double bias) { - int first, second; - - first = (int) linear(pool->size, bias); - second = (int) linear(pool->size, bias); - - if (pool->size > 1) { - while(first==second) - second = (int) linear(pool->size, bias); - } - - geqo_copy (momma, &pool->data[first], pool->string_length); - geqo_copy (daddy, &pool->data[second], pool->string_length); + int first, + second; + + first = (int) linear(pool->size, bias); + second = (int) linear(pool->size, bias); + + if (pool->size > 1) + { + while (first == second) + second = (int) linear(pool->size, bias); + } + + geqo_copy(momma, &pool->data[first], pool->string_length); + geqo_copy(daddy, &pool->data[second], pool->string_length); } /* linear-- - * generates random integer between 0 and input max number - * using input linear bias + * generates random integer between 0 and input max number + * using input linear bias * - * probability distribution function is: f(x) = bias - 2(bias - 1)x - * bias = (prob of first rule) / (prob of middle rule) + * probability distribution function is: f(x) = bias - 2(bias - 1)x + * bias = (prob of first rule) / (prob of middle rule) * */ static int -linear(int pool_size, double bias) /* bias is y-intercept of linear distribution */ +linear(int pool_size, double bias) /* bias is y-intercept of linear + * distribution */ { - double index; /* index between 0 and pop_size */ - double max = (double) pool_size; + double index; /* index between 0 and pop_size */ + double max = (double) pool_size; - index = - max*( bias - sqrt ( (bias*bias) - 4.0*(bias-1.0)*geqo_rand() ) ) - / 2.0 / (bias-1.0); + index = + max * (bias - sqrt((bias * bias) - 4.0 * (bias - 1.0) * geqo_rand())) + / 2.0 / (bias - 1.0); - return((int) index); + return ((int) index); } - |