pqc/external/flint-2.4.3/fmpq/test/t-reconstruct_fmpz_2.c

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2014-05-18 22:03:37 +00:00
/*=============================================================================
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) 2011 Fredrik Johansson
******************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <gmp.h>
#include "flint.h"
#include "fmpz.h"
#include "fmpq.h"
#include "profiler.h"
int
main(void)
{
int i;
FLINT_TEST_INIT(state);
flint_printf("reconstruct_fmpz_2....");
fflush(stdout);
for (i = 0; i < 10000; i++)
{
int result;
int modresult;
int special_case;
fmpq_t x, y;
fmpz_t mod, res, N, D, t;
mpz_t tmp;
fmpq_init(x);
fmpq_init(y);
fmpz_init(mod);
fmpz_init(res);
fmpz_init(N);
fmpz_init(D);
fmpz_init(t);
mpz_init(tmp);
fmpq_randtest(x, state, 100);
fmpz_abs(N, fmpq_numref(x));
fmpz_set(D, fmpq_denref(x));
/* Randomly generate larger bounds */
if (n_randint(state, 2))
{
fmpz_randtest_not_zero(t, state, 100);
fmpz_abs(t, t);
fmpz_mul(N, N, t);
}
if (n_randint(state, 2))
{
fmpz_randtest_not_zero(t, state, 100);
fmpz_abs(t, t);
fmpz_mul(D, D, t);
}
fmpz_mul(mod, N, D);
fmpz_mul_ui(mod, mod, UWORD(2));
/* Next prime greater than or equal */
fmpz_get_mpz(tmp, mod);
flint_mpz_sub_ui(tmp, tmp, UWORD(1));
mpz_nextprime(tmp, tmp);
fmpz_set_mpz(mod, tmp);
modresult = fmpq_mod_fmpz(res, x, mod);
result = fmpq_reconstruct_fmpz_2(y, res, mod, N, D);
/* Special case: both 1 and -1 have residue 1 mod 2.
There's probably no particular reason to disallow this. */
special_case = (fmpz_cmp_ui(mod, UWORD(2)) == 0 &&
fmpz_get_si(&x->num) == WORD(-1) &&
fmpz_cmp_ui(&x->den, UWORD(1)) == 0);
if (special_case)
{
if (!modresult || !result ||
!fmpz_is_one(&y->num) || !fmpz_is_one(&y->den))
{
flint_printf("FAIL: special case: -1 mod 2\n");
abort();
}
}
else if (!modresult || !result || !fmpq_equal(x, y))
{
flint_printf("FAIL: reconstruction failed\n");
flint_printf("input = ");
fmpq_print(x);
flint_printf("\nmodulus = ");
fmpz_print(mod);
flint_printf("\nresidue = ");
fmpz_print(res);
flint_printf("\nreconstructed = ");
fmpq_print(y);
flint_printf("\nfmpq_mod_fmpz return value = %d", modresult);
flint_printf("\nfmpq_reconstruct_fmpz return value = %d", result);
flint_printf("\n");
abort();
}
fmpq_clear(x);
fmpq_clear(y);
fmpz_clear(mod);
fmpz_clear(res);
fmpz_clear(N);
fmpz_clear(D);
fmpz_clear(t);
mpz_clear(tmp);
}
FLINT_TEST_CLEANUP(state);
flint_printf("PASS\n");
return 0;
}