66 lines
2.1 KiB
C
66 lines
2.1 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) 2011 Fredrik Johansson
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******************************************************************************/
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#include "arith.h"
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void
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arith_bell_number_multi_mod(fmpz_t res, ulong n)
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{
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fmpz_comb_temp_t temp;
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fmpz_comb_t comb;
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nmod_t mod;
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mp_ptr primes, residues;
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slong k, num_primes;
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mp_bitcnt_t size, prime_bits;
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size = arith_bell_number_size(n);
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prime_bits = FLINT_BITS - 1;
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num_primes = (size + prime_bits - 1) / prime_bits;
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primes = flint_malloc(num_primes * sizeof(mp_limb_t));
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residues = flint_malloc(num_primes * sizeof(mp_limb_t));
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primes[0] = n_nextprime(UWORD(1) << prime_bits, 0);
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for (k = 1; k < num_primes; k++)
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primes[k] = n_nextprime(primes[k-1], 0);
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for (k = 0; k < num_primes; k++)
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{
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nmod_init(&mod, primes[k]);
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residues[k] = arith_bell_number_nmod(n, mod);
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}
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fmpz_comb_init(comb, primes, num_primes);
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fmpz_comb_temp_init(temp, comb);
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fmpz_multi_CRT_ui(res, residues, comb, temp, 0);
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fmpz_comb_clear(comb);
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fmpz_comb_temp_clear(temp);
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flint_free(primes);
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flint_free(residues);
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}
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