57 lines
1.7 KiB
C
57 lines
1.7 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) 2012 William Hart
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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 "longlong.h"
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#include "mpn_extras.h"
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void flint_mpn_preinvn(mp_ptr dinv, mp_srcptr d, mp_size_t n)
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{
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mp_ptr q, r, d1;
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d1 = flint_malloc(n*sizeof(mp_limb_t));
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if (mpn_add_1(d1, d, n, 1)) /* check for d + 1 == 0 */
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{
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mpn_zero(dinv, n);
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flint_free(d1);
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return;
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}
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r = flint_malloc((2*n + 1)*sizeof(mp_limb_t));
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q = flint_malloc((n + 2)*sizeof(mp_limb_t));
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mpn_zero(r, 2*n);
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r[2*n] = 1;
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mpn_tdiv_qr(q, r, 0, r, 2*n + 1, d1, n);
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mpn_copyi(dinv, q, n);
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flint_free(r);
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flint_free(q);
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flint_free(d1);
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}
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