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Diffstat (limited to 'gsl-1.9/combination/combination.c')
-rw-r--r-- | gsl-1.9/combination/combination.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/gsl-1.9/combination/combination.c b/gsl-1.9/combination/combination.c new file mode 100644 index 0000000..6f8c817 --- /dev/null +++ b/gsl-1.9/combination/combination.c @@ -0,0 +1,189 @@ +/* combination/combination.c + * based on permutation/permutation.c by Brian Gough + * + * Copyright (C) 2001 Szymon Jaroszewicz + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or (at + * your option) any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + */ + +#include <config.h> +#include <gsl/gsl_errno.h> +#include <gsl/gsl_combination.h> + +size_t +gsl_combination_n (const gsl_combination * c) +{ + return c->n ; +} + +size_t +gsl_combination_k (const gsl_combination * c) +{ + return c->k ; +} + +size_t * +gsl_combination_data (const gsl_combination * c) +{ + return c->data ; +} + +#ifndef HIDE_INLINE_STATIC +size_t +gsl_combination_get (const gsl_combination * c, const size_t i) +{ + if (gsl_check_range) + { + if (i >= c->k) /* size_t is unsigned, can't be negative */ + { + GSL_ERROR_VAL ("index out of range", GSL_EINVAL, 0); + } + } + + return c->data[i]; +} +#endif + + +int +gsl_combination_valid (gsl_combination * c) +{ + const size_t n = c->n ; + const size_t k = c->k ; + + size_t i, j ; + + if( k > n ) + { + GSL_ERROR("combination has k greater than n", GSL_FAILURE) ; + } + for (i = 0; i < k; i++) + { + const size_t ci = c->data[i]; + + if (ci >= n) + { + GSL_ERROR("combination index outside range", GSL_FAILURE) ; + } + + for (j = 0; j < i; j++) + { + if (c->data[j] == ci) + { + GSL_ERROR("duplicate combination index", GSL_FAILURE) ; + } + if (c->data[j] > ci) + { + GSL_ERROR("combination indices not in increasing order", + GSL_FAILURE) ; + } + } + } + + return GSL_SUCCESS; +} + + +int +gsl_combination_next (gsl_combination * c) +{ + /* Replaces c with the next combination (in the standard lexicographical + * ordering). Returns GSL_FAILURE if there is no next combination. + */ + const size_t n = c->n; + const size_t k = c->k; + size_t *data = c->data; + size_t i; + + if(k == 0) + { + return GSL_FAILURE; + } + i = k - 1; + + while(i > 0 && data[i] == n - k + i) + { + i--; + } + if(i == 0 && data[i] == n - k) + { + return GSL_FAILURE; + } + data[i]++; + for(; i < k - 1; i++) + { + data[i + 1] = data[i] + 1; + } + return GSL_SUCCESS; +} + +int +gsl_combination_prev (gsl_combination * c) +{ + /* Replaces c with the previous combination (in the standard + * lexicographical ordering). Returns GSL_FAILURE if there is no + * previous combination. + */ + const size_t n = c->n; + const size_t k = c->k; + size_t *data = c->data; + size_t i; + + if(k == 0) + { + return GSL_FAILURE; + } + i = k - 1; + + while(i > 0 && data[i] == data[i-1] + 1) + { + i--; + } + if(i == 0 && data[i] == 0) + { + return GSL_FAILURE; + } + data[i++]--; + for(; i < k; i++) + { + data[i] = n - k + i; + } + return GSL_SUCCESS; +} + +int +gsl_combination_memcpy (gsl_combination * dest, const gsl_combination * src) +{ + const size_t src_n = src->n; + const size_t src_k = src->k; + const size_t dest_n = dest->n; + const size_t dest_k = dest->k; + + if (src_n != dest_n || src_k != dest_k) + { + GSL_ERROR ("combination lengths are not equal", GSL_EBADLEN); + } + + { + size_t j; + + for (j = 0; j < src_k; j++) + { + dest->data[j] = src->data[j]; + } + } + + return GSL_SUCCESS; +} |