1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150
|
/*=============================================================================
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) 2010 William Hart
******************************************************************************/
#include <stdlib.h>
#include <gmp.h>
#include "flint.h"
#include "nmod_vec.h"
#include "nmod_poly.h"
#include "ulong_extras.h"
/* Assumes poly1 and poly2 are not length 0. */
void
_nmod_poly_mulhigh_classical(mp_ptr res, mp_srcptr poly1,
slong len1, mp_srcptr poly2, slong len2, slong start,
nmod_t mod)
{
slong m, n;
_nmod_vec_zero(res, start);
if (len1 == 1) /* Special case if the length of both inputs is 1 */
{
if (start == 0)
res[0] = n_mulmod2_preinv(poly1[0], poly2[0], mod.n, mod.ninv);
}
else /* Ordinary case */
{
slong i;
slong bits = FLINT_BITS - (slong) mod.norm;
slong log_len = FLINT_BIT_COUNT(len2);
if (2 * bits + log_len <= FLINT_BITS)
{
/* Set res[i] = poly1[i]*poly2[0] */
if (start < len1)
mpn_mul_1(res + start, poly1 + start, len1 - start, poly2[0]);
if (len2 != 1)
{
/* Set res[i+len1-1] = in1[len1-1]*in2[i] */
m = FLINT_MAX(len1 - 1, start);
mpn_mul_1(res + m, poly2 + m - len1 + 1, len2 - 1 + len1 - m,
poly1[len1 - 1]);
/* out[i+j] += in1[i]*in2[j] */
m = FLINT_MAX(start, len2 - 1);
for (i = m - len2 + 1; i < len1 - 1; i++)
{
n = FLINT_MAX(i + 1, start);
mpn_addmul_1(res + n, poly2 + n - i, len2 + i - n,
poly1[i]);
}
}
_nmod_vec_reduce(res, res, len1 + len2 - 1, mod);
}
else
{
/* Set res[i] = poly1[i]*poly2[0] */
if (start < len1)
_nmod_vec_scalar_mul_nmod(res + start, poly1 + start, len1 - start,
poly2[0], mod);
if (len2 == 1)
return;
/* Set res[i+len1-1] = in1[len1-1]*in2[i] */
m = FLINT_MAX(len1 - 1, start);
_nmod_vec_scalar_mul_nmod(res + m, poly2 + m - len1 + 1,
len2 - 1 + len1 - m, poly1[len1 - 1], mod);
/* out[i+j] += in1[i]*in2[j] */
m = FLINT_MAX(start, len2 - 1);
for (i = m - len2 + 1; i < len1 - 1; i++)
{
n = FLINT_MAX(i + 1, start);
_nmod_vec_scalar_addmul_nmod(res + n, poly2 + n - i, len2 + i - n,
poly1[i], mod);
}
}
}
}
void
nmod_poly_mulhigh_classical(nmod_poly_t res,
const nmod_poly_t poly1, const nmod_poly_t poly2,
slong start)
{
slong len_out = poly1->length + poly2->length - 1;
if (poly1->length == 0 || poly2->length == 0 || start >= len_out)
{
nmod_poly_zero(res);
return;
}
if (res == poly1 || res == poly2)
{
nmod_poly_t temp;
nmod_poly_init2_preinv(temp, poly1->mod.n, poly1->mod.ninv, len_out);
if (poly1->length >= poly2->length)
_nmod_poly_mulhigh_classical(temp->coeffs, poly1->coeffs,
poly1->length, poly2->coeffs,
poly2->length, start, poly1->mod);
else
_nmod_poly_mulhigh_classical(temp->coeffs, poly2->coeffs,
poly2->length, poly1->coeffs,
poly1->length, start, poly1->mod);
nmod_poly_swap(res, temp);
nmod_poly_clear(temp);
}
else
{
nmod_poly_fit_length(res, len_out);
if (poly1->length >= poly2->length)
_nmod_poly_mulhigh_classical(res->coeffs, poly1->coeffs,
poly1->length, poly2->coeffs,
poly2->length, start, poly1->mod);
else
_nmod_poly_mulhigh_classical(res->coeffs, poly2->coeffs,
poly2->length, poly1->coeffs,
poly1->length, start, poly1->mod);
}
res->length = len_out;
_nmod_poly_normalise(res);
}
|