97 lines
2.7 KiB
C
97 lines
2.7 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) 2008, 2009 William Hart
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Copyright (C) 2010, 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 "fmpz.h"
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#include "fmpz_vec.h"
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#include "fmpz_poly.h"
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void _fmpz_poly_sqrlow(fmpz * res, const fmpz * poly, slong len, slong n)
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{
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mp_size_t limbs;
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if (n < 7)
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{
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_fmpz_poly_sqrlow_classical(res, poly, len, n);
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return;
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}
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limbs = _fmpz_vec_max_limbs(poly, len);
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if (n < 16 && limbs > 12)
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{
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int i;
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fmpz *copy;
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copy = flint_malloc(n * sizeof(fmpz));
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for (i = 0; i < len; i++)
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copy[i] = poly[i];
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flint_mpn_zero((mp_ptr) copy + len, n - len);
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_fmpz_poly_sqrlow_karatsuba_n(res, copy, n);
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flint_free(copy);
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}
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else if (limbs <= 4)
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_fmpz_poly_sqrlow_KS(res, poly, len, n);
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else if (limbs/2048 > len)
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_fmpz_poly_sqrlow_KS(res, poly, len, n);
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else if (limbs*FLINT_BITS*4 < len)
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_fmpz_poly_sqrlow_KS(res, poly, len, n);
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else
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_fmpz_poly_mullow_SS(res, poly, len, poly, len, n);
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}
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void fmpz_poly_sqrlow(fmpz_poly_t res, const fmpz_poly_t poly, slong n)
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{
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const slong len = poly->length;
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if (len == 0 || n == 0)
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{
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fmpz_poly_zero(res);
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return;
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}
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if (res == poly)
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{
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fmpz_poly_t t;
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fmpz_poly_init2(t, n);
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fmpz_poly_sqrlow(t, poly, n);
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fmpz_poly_swap(res, t);
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fmpz_poly_clear(t);
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return;
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}
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n = FLINT_MIN(2 * len - 1, n);
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fmpz_poly_fit_length(res, n);
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_fmpz_poly_sqrlow(res->coeffs, poly->coeffs, len, n);
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_fmpz_poly_set_length(res, n);
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_fmpz_poly_normalise(res);
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}
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