66 lines
2.2 KiB
C
66 lines
2.2 KiB
C
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/*=============================================================================
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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 Sebastian Pancratz
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******************************************************************************/
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#include <stdlib.h>
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#include <gmp.h>
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#include "flint.h"
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#include "nmod_vec.h"
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#include "nmod_poly.h"
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#include "ulong_extras.h"
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void _nmod_poly_rem_q1(mp_ptr R,
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mp_srcptr A, slong lenA, mp_srcptr B, slong lenB,
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nmod_t mod)
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{
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const mp_limb_t invL = (B[lenB-1] == 1) ? 1 : n_invmod(B[lenB-1], mod.n);
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if (lenB > 1)
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{
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mp_limb_t t, q0, q1;
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q1 = n_mulmod2_preinv(A[lenA-1], invL, mod.n, mod.ninv);
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t = n_mulmod2_preinv(q1, B[lenB-2], mod.n, mod.ninv);
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t = n_submod(A[lenA-2], t, mod.n);
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q0 = n_mulmod2_preinv(t, invL, mod.n, mod.ninv);
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if (FLINT_BITS + 2 <= 2 * mod.norm)
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{
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mpn_mul_1(R, B, lenB - 1, q0);
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if (lenB > 2)
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mpn_addmul_1(R + 1, B, lenB - 2, q1);
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_nmod_vec_reduce(R, R, lenB - 1, mod);
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}
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else
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{
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_nmod_vec_scalar_mul_nmod(R, B, lenB - 1, q0, mod);
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if (lenB > 2)
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_nmod_vec_scalar_addmul_nmod(R + 1, B, lenB - 2, q1, mod);
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}
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_nmod_vec_sub(R, A, R, lenB - 1, mod);
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}
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}
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