158 lines
4.2 KiB
C
158 lines
4.2 KiB
C
/*=============================================================================
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This file is part of FLINT.
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FLINT is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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FLINT is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with FLINT; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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=============================================================================*/
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/******************************************************************************
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Copyright (C) 2008, 2009, William Hart
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Copyright (C) 2010 Fredrik Johansson
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******************************************************************************/
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#include <gmp.h>
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#include "flint.h"
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#include "ulong_extras.h"
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#include "fmpz.h"
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#include "nmod_vec.h"
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#include "fmpz_vec.h"
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void fmpz_comb_temp_init(fmpz_comb_temp_t temp, const fmpz_comb_t comb)
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{
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slong n, i, j;
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/* Allocate space for comb_temp */
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temp->n = n = comb->n;
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temp->comb_temp = (fmpz **) flint_malloc(n * sizeof(fmpz *));
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j = (WORD(1) << (n - 1));
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for (i = 0; i < n; i++)
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{
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temp->comb_temp[i] = _fmpz_vec_init(j);
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j /= 2;
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}
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fmpz_init(temp->temp);
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fmpz_init(temp->temp2);
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}
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void
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fmpz_comb_init(fmpz_comb_t comb, mp_srcptr primes, slong num_primes)
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{
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slong i, j;
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slong n, num;
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ulong log_comb, log_res;
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fmpz_t temp, temp2;
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comb->primes = primes;
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comb->num_primes = num_primes;
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n = FLINT_BIT_COUNT(num_primes);
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comb->n = n;
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/* Create nmod_poly modulus information */
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comb->mod = (nmod_t *) flint_malloc(sizeof(nmod_t) * num_primes);
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for (i = 0; i < num_primes; i++)
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nmod_init(&comb->mod[i], primes[i]);
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/* Nothing to do */
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if (n == 0)
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return;
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/* Allocate space for comb and res */
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comb->comb = (fmpz **) flint_malloc(n * sizeof(fmpz *));
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comb->res = (fmpz **) flint_malloc(n * sizeof(fmpz *));
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/* Size of top level */
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j = (WORD(1) << (n - 1));
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/* Initialise arrays at each level */
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for (i = 0; i < n; i++)
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{
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comb->comb[i] = _fmpz_vec_init(j);
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comb->res[i] = _fmpz_vec_init(j);
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j /= 2;
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}
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/* Compute products of pairs of primes and place in comb */
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for (i = 0, j = 0; i + 2 <= num_primes; i += 2, j++)
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{
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fmpz_set_ui(comb->comb[0] + j, primes[i]);
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fmpz_mul_ui(comb->comb[0] + j, comb->comb[0] + j, primes[i+1]);
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}
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/* In case number of primes is odd */
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if (i < num_primes)
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{
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fmpz_set_ui(comb->comb[0] + j, primes[i]);
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i += 2;
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j++;
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}
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/* Set the rest of the entries on that row of the comb to 1 */
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num = (WORD(1) << n);
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for (; i < num; i += 2, j++)
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{
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fmpz_one(comb->comb[0] + j);
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}
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/* Compute rest of comb by multiplying in pairs */
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log_comb = 1;
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num /= 2;
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while (num >= 2)
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{
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for (i = 0, j = 0; i < num; i += 2, j++)
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{
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fmpz_mul(comb->comb[log_comb] + j, comb->comb[log_comb-1] + i,
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comb->comb[log_comb-1] + i + 1);
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}
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log_comb++;
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num /= 2;
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}
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/* Compute inverses from pairs of primes */
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fmpz_init(temp);
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fmpz_init(temp2);
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for (i = 0, j = 0; i + 2 <= num_primes; i += 2, j++)
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{
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fmpz_set_ui(temp, primes[i]);
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fmpz_set_ui(temp2, primes[i+1]);
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fmpz_invmod(comb->res[0] + j, temp, temp2);
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}
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fmpz_clear(temp);
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fmpz_clear(temp2);
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/* Compute remaining inverses, each level
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combining pairs from the level below */
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log_res = 1;
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num = (WORD(1) << (n - 1));
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while (log_res < n)
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{
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for (i = 0, j = 0; i < num; i += 2, j++)
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{
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fmpz_invmod(comb->res[log_res] + j, comb->comb[log_res-1] + i,
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comb->comb[log_res-1] + i + 1);
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}
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log_res++;
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num /= 2;
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}
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}
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