109 lines
2.9 KiB
C
109 lines
2.9 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_KS(fmpz * res, const fmpz * poly, slong len, slong n)
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{
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int neg;
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slong bits, limbs, loglen, sign = 0;
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mp_limb_t *arr_in, *arr_out;
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FMPZ_VEC_NORM(poly, len);
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if (len == 0)
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{
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_fmpz_vec_zero(res, n);
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return;
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}
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neg = (fmpz_sgn(poly + len - 1) > 0) ? 0 : -1;
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if (n > 2 * len - 1)
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{
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_fmpz_vec_zero(res + 2 * len - 1, n - (2 * len - 1));
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n = 2 * len - 1;
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}
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bits = _fmpz_vec_max_bits(poly, len);
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if (bits < 0)
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{
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sign = 1;
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bits = - bits;
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}
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loglen = FLINT_BIT_COUNT(len);
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bits = 2 * bits + loglen + sign;
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limbs = (bits * len - 1) / FLINT_BITS + 1;
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arr_in = flint_calloc(limbs, sizeof(mp_limb_t));
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arr_out = flint_malloc((2 * limbs) * sizeof(mp_limb_t));
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_fmpz_poly_bit_pack(arr_in, poly, len, bits, neg);
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mpn_sqr(arr_out, arr_in, limbs);
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if (sign)
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_fmpz_poly_bit_unpack(res, n, arr_out, bits, 0);
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else
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_fmpz_poly_bit_unpack_unsigned(res, n, arr_out, bits);
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flint_free(arr_in);
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flint_free(arr_out);
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}
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void fmpz_poly_sqrlow_KS(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_KS(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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fmpz_poly_fit_length(res, n);
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_fmpz_poly_sqrlow_KS(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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