| /* permutation/permutation.c |
| * |
| * Copyright (C) 1996, 1997, 1998, 1999, 2000 Brian Gough |
| * |
| * 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_permutation.h> |
| |
| size_t |
| gsl_permutation_size (const gsl_permutation * p) |
| { |
| return p->size ; |
| } |
| |
| size_t * |
| gsl_permutation_data (const gsl_permutation * p) |
| { |
| return p->data ; |
| } |
| |
| #ifndef HIDE_INLINE_STATIC |
| size_t |
| gsl_permutation_get (const gsl_permutation * p, const size_t i) |
| { |
| if (gsl_check_range) |
| { |
| if (i >= p->size) /* size_t is unsigned, can't be negative */ |
| { |
| GSL_ERROR_VAL ("index out of range", GSL_EINVAL, 0); |
| } |
| } |
| |
| return p->data[i]; |
| } |
| #endif |
| |
| int |
| gsl_permutation_swap (gsl_permutation * p, const size_t i, const size_t j) |
| { |
| const size_t size = p->size ; |
| |
| if (i >= size) |
| { |
| GSL_ERROR("first index is out of range", GSL_EINVAL); |
| } |
| |
| if (j >= size) |
| { |
| GSL_ERROR("second index is out of range", GSL_EINVAL); |
| } |
| |
| if (i != j) |
| { |
| size_t tmp = p->data[i]; |
| p->data[i] = p->data[j]; |
| p->data[j] = tmp; |
| } |
| |
| return GSL_SUCCESS; |
| } |
| |
| |
| int |
| gsl_permutation_valid (gsl_permutation * p) |
| { |
| const size_t size = p->size ; |
| |
| size_t i, j ; |
| |
| for (i = 0; i < size; i++) |
| { |
| if (p->data[i] >= size) |
| { |
| GSL_ERROR("permutation index outside range", GSL_FAILURE) ; |
| } |
| |
| for (j = 0; j < i; j++) |
| { |
| if (p->data[i] == p->data[j]) |
| { |
| GSL_ERROR("duplicate permutation index", GSL_FAILURE) ; |
| } |
| } |
| } |
| |
| return GSL_SUCCESS; |
| } |
| |
| void |
| gsl_permutation_reverse (gsl_permutation * p) |
| { |
| const size_t size = p->size ; |
| |
| size_t i ; |
| |
| for (i = 0; i < (size / 2); i++) |
| { |
| size_t j = size - i - 1; |
| |
| size_t tmp = p->data[i] ; |
| p->data[i] = p->data[j] ; |
| p->data[j] = tmp ; |
| } |
| } |
| |
| int |
| gsl_permutation_inverse (gsl_permutation * inv, const gsl_permutation * p) |
| { |
| const size_t size = p->size ; |
| |
| size_t i ; |
| |
| if (inv->size != size) |
| { |
| GSL_ERROR("permutation lengths are not equal", GSL_EBADLEN); |
| } |
| |
| for (i = 0; i < size; i++) |
| { |
| inv->data[p->data[i]] = i ; |
| } |
| |
| return GSL_SUCCESS ; |
| } |
| |
| int |
| gsl_permutation_next (gsl_permutation * p) |
| { |
| /* Replaces p with the next permutation (in the standard lexicographical |
| * ordering). Returns GSL_FAILURE if there is no next permutation. |
| */ |
| const size_t size = p->size; |
| size_t i, j, k; |
| |
| if (size < 2) |
| { |
| return GSL_FAILURE; |
| } |
| |
| i = size - 2; |
| |
| while ((p->data[i] > p->data[i+1]) && (i != 0)) |
| { |
| i--; |
| } |
| |
| if ((i == 0) && (p->data[0] > p->data[1])) |
| { |
| return GSL_FAILURE; |
| } |
| |
| k = i + 1; |
| |
| for (j = i + 2; j < size; j++ ) |
| { |
| if ((p->data[j] > p->data[i]) && (p->data[j] < p->data[k])) |
| { |
| k = j; |
| } |
| } |
| |
| /* swap i and k */ |
| |
| { |
| size_t tmp = p->data[i]; |
| p->data[i] = p->data[k]; |
| p->data[k] = tmp; |
| } |
| |
| for (j = i + 1; j <= ((size + i) / 2); j++) |
| { |
| size_t tmp = p->data[j]; |
| p->data[j] = p->data[size + i - j]; |
| p->data[size + i - j] = tmp; |
| } |
| |
| return GSL_SUCCESS; |
| } |
| |
| int |
| gsl_permutation_prev (gsl_permutation * p) |
| { |
| const size_t size = p->size; |
| size_t i, j, k; |
| |
| if (size < 2) |
| { |
| return GSL_FAILURE; |
| } |
| |
| i = size - 2; |
| |
| while ((p->data[i] < p->data[i+1]) && (i != 0)) |
| { |
| i--; |
| } |
| |
| if ((i == 0) && (p->data[0] < p->data[1])) |
| { |
| return GSL_FAILURE; |
| } |
| |
| k = i + 1; |
| |
| for (j = i + 2; j < size; j++ ) |
| { |
| if ((p->data[j] < p->data[i]) && (p->data[j] > p->data[k])) |
| { |
| k = j; |
| } |
| } |
| |
| /* swap i and k */ |
| |
| { |
| size_t tmp = p->data[i]; |
| p->data[i] = p->data[k]; |
| p->data[k] = tmp; |
| } |
| |
| for (j = i + 1; j <= ((size + i) / 2); j++) |
| { |
| size_t tmp = p->data[j]; |
| p->data[j] = p->data[size + i - j]; |
| p->data[size + i - j] = tmp; |
| } |
| |
| return GSL_SUCCESS; |
| } |
| |
| int |
| gsl_permutation_mul (gsl_permutation * p, const gsl_permutation * pa, const gsl_permutation * pb) |
| { |
| size_t i; |
| const size_t size = p->size; |
| |
| if (pa->size != size) |
| { |
| GSL_ERROR("size of result does not match size of pa", GSL_EINVAL); |
| } |
| |
| if (pb->size != size) |
| { |
| GSL_ERROR("size of result does not match size of pb", GSL_EINVAL); |
| } |
| |
| for (i = 0; i < size; i++) |
| { |
| p->data[i] = pb->data[pa->data[i]]; |
| } |
| |
| return GSL_SUCCESS; |
| } |
| int |
| gsl_permutation_memcpy (gsl_permutation * dest, |
| const gsl_permutation * src) |
| { |
| const size_t src_size = src->size; |
| const size_t dest_size = dest->size; |
| |
| if (src_size != dest_size) |
| { |
| GSL_ERROR ("permutation lengths are not equal", GSL_EBADLEN); |
| } |
| |
| { |
| size_t j; |
| |
| for (j = 0; j < src_size; j++) |
| { |
| dest->data[j] = src->data[j]; |
| } |
| } |
| |
| return GSL_SUCCESS; |
| } |