63 lines
1.8 KiB
C
63 lines
1.8 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_nmod_vec_series(mp_ptr res, slong n, nmod_t mod)
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{
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mp_limb_t fac, c;
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mp_ptr tmp;
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slong k;
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if (n < 1)
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return;
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tmp = flint_malloc(sizeof(mp_limb_t) * n);
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/* Divide by factorials */
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fac = n_factorial_mod2_preinv(n-1, mod.n, mod.ninv);
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c = n_invmod(fac, mod.n);
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for (k = n - 1; k > 0; k--)
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{
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tmp[k] = c;
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c = n_mulmod2_preinv(c, k, mod.n, mod.ninv);
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}
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tmp[0] = UWORD(0);
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_nmod_poly_exp_series(res, tmp, n, mod);
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/* Multiply by factorials */
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c = UWORD(1);
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for (k = 1; k < n; k++)
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{
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c = n_mulmod2_preinv(c, k, mod.n, mod.ninv);
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res[k] = n_mulmod2_preinv(res[k], c, mod.n, mod.ninv);
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}
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flint_free(tmp);
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}
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