103 lines
3.0 KiB
C
103 lines
3.0 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) 2008-2011 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 "fmpz.h"
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#include "fmpz_vec.h"
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#include "fmpz_poly.h"
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#include "fft.h"
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slong _fmpz_vec_get_fft(mp_limb_t ** coeffs_f,
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const fmpz * coeffs_m, slong l, slong length)
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{
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slong size_f = l + 1;
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mp_limb_t * coeff;
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mp_limb_t mask = WORD(-1);
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slong bits = 0, limbs = 0, size_j, i, c;
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int sign = 1, signed_c;
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for (i = 0; i < length; i++, coeffs_m++)
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{
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c = *coeffs_m;
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signed_c = 0;
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if (!COEFF_IS_MPZ(c)) /* coeff is small */
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{
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size_j = 1;
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if (c < 0)
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{
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signed_c = 1;
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c = -c;
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coeff = (mp_limb_t *) &c;
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} else
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coeff = (mp_limb_t *) coeffs_m;
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} else /* coeff is an mpz_t */
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{
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__mpz_struct * mpz_ptr = COEFF_TO_PTR(c);
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size_j = mpz_ptr->_mp_size;
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if (size_j < 0)
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{
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signed_c = 1;
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size_j = -size_j;
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}
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coeff = mpz_ptr->_mp_d;
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}
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if (signed_c) sign = -1;
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if (size_j > limbs + 1) /* coeff is at least 1 limb bigger */
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{
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limbs = size_j - 1;
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bits = FLINT_BIT_COUNT(coeff[size_j - 1]);
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if (bits == FLINT_BITS) mask = WORD(0);
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else mask = WORD(-1) - ((WORD(1)<<bits) - 1);
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} else if (size_j == limbs + 1) /* coeff is same size as prev biggest */
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{
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if (coeff[size_j - 1] & mask) /* see if we have more bits than before */
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{
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bits = FLINT_BIT_COUNT(coeff[size_j - 1]);
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if (bits == FLINT_BITS) mask = WORD(0);
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else mask = WORD(-1) - ((WORD(1)<<bits) - 1);
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}
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}
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if (signed_c) /* write out FFT coefficient, ensuring sign is correct */
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{
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mpn_neg_n(coeffs_f[i], coeff, size_j);
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flint_mpn_store(coeffs_f[i] + size_j, size_f - size_j, WORD(-1));
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} else
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{
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flint_mpn_copyi(coeffs_f[i], coeff, size_j);
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flint_mpn_zero(coeffs_f[i] + size_j, size_f - size_j);
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}
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}
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return sign*(FLINT_BITS*limbs + bits);
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}
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