pqc/external/flint-2.4.3/qsieve/ll_square_root.c
2014-05-24 23:16:06 +02:00

94 lines
2.7 KiB
C

/*=============================================================================
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) 2006, 2011 William Hart
******************************************************************************/
#define ulong ulongxx /* interferes with system includes */
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#undef ulong
#define ulong mp_limb_t
#include <gmp.h>
#include "flint.h"
#include "ulong_extras.h"
#include "qsieve.h"
#include "fmpz.h"
void qsieve_ll_square_root(fmpz_t X, fmpz_t Y, qs_t qs_inf,
uint64_t * nullrows, slong ncols, slong l, fmpz_t N)
{
slong position, i, j;
slong * relation = qs_inf->relation;
prime_t * factor_base = qs_inf->factor_base;
slong * prime_count = qs_inf->prime_count;
slong num_primes = qs_inf->num_primes;
fmpz * Y_arr = qs_inf->Y_arr;
fmpz_t pow;
fmpz_init(pow);
memset(prime_count, 0, num_primes*sizeof(slong));
fmpz_one(X);
fmpz_one(Y);
for (i = 0; i < ncols; i++)
{
if (get_null_entry(nullrows, i, l))
{
position = qs_inf->matrix[i].orig*2*qs_inf->max_factors;
for (j = 0; j < relation[position]; j++)
{
prime_count[relation[position+2*j+1]] +=
(relation[position+2*j+2]);
}
fmpz_mul(Y, Y, Y_arr + qs_inf->matrix[i].orig);
if (i % 10 == 0) fmpz_mod(Y, Y, N);
}
}
for (i = 0; i < num_primes; i++)
{
if (prime_count[i])
{
fmpz_set_ui(pow, factor_base[i].p);
fmpz_powm_ui(pow, pow, prime_count[i]/2, N);
fmpz_mul(X, X, pow);
}
if (i%10 == 0 || i == num_primes - 1) fmpz_mod(X, X, N);
}
#if QS_DEBUG
for (i = 0; i < num_primes; i++)
if ((prime_count[i] %2) != 0) flint_printf("Error %wd, %wd, %wd\n", l, i, prime_count[i]);
#endif
fmpz_clear(pow);
}