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- /* combination/init.c
- * based on permutation/init.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 3 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 "gsl__config.h"
- #include <stdlib.h>
- #include "gsl_errno.h"
- #include "gsl_combination.h"
- gsl_combination *
- gsl_combination_alloc (const size_t n, const size_t k)
- {
- gsl_combination * c;
- if (n == 0)
- {
- GSL_ERROR_VAL ("combination parameter n must be positive integer",
- GSL_EDOM, 0);
- }
- if (k > n)
- {
- GSL_ERROR_VAL ("combination length k must be an integer less than or equal to n",
- GSL_EDOM, 0);
- }
- c = (gsl_combination *) malloc (sizeof (gsl_combination));
- if (c == 0)
- {
- GSL_ERROR_VAL ("failed to allocate space for combination struct",
- GSL_ENOMEM, 0);
- }
- if (k > 0)
- {
- c->data = (size_t *) malloc (k * sizeof (size_t));
- if (c->data == 0)
- {
- free (c); /* exception in constructor, avoid memory leak */
- GSL_ERROR_VAL ("failed to allocate space for combination data",
- GSL_ENOMEM, 0);
- }
- }
- else
- {
- c->data = 0;
- }
- c->n = n;
- c->k = k;
- return c;
- }
- gsl_combination *
- gsl_combination_calloc (const size_t n, const size_t k)
- {
- size_t i;
- gsl_combination * c = gsl_combination_alloc (n, k);
- if (c == 0)
- return 0;
- /* initialize combination to identity */
- for (i = 0; i < k; i++)
- {
- c->data[i] = i;
- }
- return c;
- }
- void
- gsl_combination_init_first (gsl_combination * c)
- {
- const size_t k = c->k ;
- size_t i;
- /* initialize combination to identity */
- for (i = 0; i < k; i++)
- {
- c->data[i] = i;
- }
- }
- void
- gsl_combination_init_last (gsl_combination * c)
- {
- const size_t k = c->k ;
- size_t i;
- size_t n = c->n;
- /* initialize combination to identity */
- for (i = 0; i < k; i++)
- {
- c->data[i] = n - k + i;
- }
- }
- void
- gsl_combination_free (gsl_combination * c)
- {
- if (c->k > 0) free (c->data);
- free (c);
- }
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