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/*=============================================================================
This file is part of FLINT.
FLINT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
FLINT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with FLINT; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2008-2011 William Hart
******************************************************************************/
#include <stdlib.h>
#include <gmp.h>
#include "flint.h"
#include "fmpz.h"
#include "fmpz_vec.h"
#include "fmpz_poly.h"
#include "fft.h"
slong _fmpz_vec_get_fft(mp_limb_t ** coeffs_f,
const fmpz * coeffs_m, slong l, slong length)
{
slong size_f = l + 1;
mp_limb_t * coeff;
mp_limb_t mask = WORD(-1);
slong bits = 0, limbs = 0, size_j, i, c;
int sign = 1, signed_c;
for (i = 0; i < length; i++, coeffs_m++)
{
c = *coeffs_m;
signed_c = 0;
if (!COEFF_IS_MPZ(c)) /* coeff is small */
{
size_j = 1;
if (c < 0)
{
signed_c = 1;
c = -c;
coeff = (mp_limb_t *) &c;
} else
coeff = (mp_limb_t *) coeffs_m;
} else /* coeff is an mpz_t */
{
__mpz_struct * mpz_ptr = COEFF_TO_PTR(c);
size_j = mpz_ptr->_mp_size;
if (size_j < 0)
{
signed_c = 1;
size_j = -size_j;
}
coeff = mpz_ptr->_mp_d;
}
if (signed_c) sign = -1;
if (size_j > limbs + 1) /* coeff is at least 1 limb bigger */
{
limbs = size_j - 1;
bits = FLINT_BIT_COUNT(coeff[size_j - 1]);
if (bits == FLINT_BITS) mask = WORD(0);
else mask = WORD(-1) - ((WORD(1)<<bits) - 1);
} else if (size_j == limbs + 1) /* coeff is same size as prev biggest */
{
if (coeff[size_j - 1] & mask) /* see if we have more bits than before */
{
bits = FLINT_BIT_COUNT(coeff[size_j - 1]);
if (bits == FLINT_BITS) mask = WORD(0);
else mask = WORD(-1) - ((WORD(1)<<bits) - 1);
}
}
if (signed_c) /* write out FFT coefficient, ensuring sign is correct */
{
mpn_neg_n(coeffs_f[i], coeff, size_j);
flint_mpn_store(coeffs_f[i] + size_j, size_f - size_j, WORD(-1));
} else
{
flint_mpn_copyi(coeffs_f[i], coeff, size_j);
flint_mpn_zero(coeffs_f[i] + size_j, size_f - size_j);
}
}
return sign*(FLINT_BITS*limbs + bits);
}
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