pqc/external/flint-2.4.3/fmpz_poly/test/t-gcd_heuristic.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) 2009 William Hart
Copyright (C) 2010 Sebastian Pancratz
******************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <gmp.h>
#include "flint.h"
#include "fmpz.h"
#include "fmpz_poly.h"
#include "ulong_extras.h"
/*
Tests whether the polynomial is suitably normalised for the
result of a GCD operation, that is, whether it's leading
coefficient is non-negative.
*/
static
int _t_gcd_is_canonical(const fmpz_poly_t poly)
{
return fmpz_poly_is_zero(poly) || (fmpz_sgn(fmpz_poly_lead(poly)) > 0);
}
int
main(void)
{
int i, result, d1, d2;
FLINT_TEST_INIT(state);
flint_printf("gcd_heuristic....");
fflush(stdout);
/* Check aliasing of a and b */
for (i = 0; i < 100 * flint_test_multiplier(); i++)
{
fmpz_poly_t a, b, c;
fmpz_poly_init(a);
fmpz_poly_init(b);
fmpz_poly_init(c);
fmpz_poly_randtest(b, state, n_randint(state, 40), 80);
fmpz_poly_randtest(c, state, n_randint(state, 40), 80);
d1 = fmpz_poly_gcd_heuristic(a, b, c);
d2 = fmpz_poly_gcd_heuristic(b, b, c);
result = ((d1 == 0 && d2 == 0) || (fmpz_poly_equal(a, b)
&& _t_gcd_is_canonical(a)));
if (!result)
{
flint_printf("FAIL (aliasing a and b):\n");
flint_printf("a = "), fmpz_poly_print(a), flint_printf("\n\n");
flint_printf("b = "), fmpz_poly_print(b), flint_printf("\n\n");
abort();
}
fmpz_poly_clear(a);
fmpz_poly_clear(b);
fmpz_poly_clear(c);
}
/* Check aliasing of a and c */
for (i = 0; i < 100 * flint_test_multiplier(); i++)
{
fmpz_poly_t a, b, c;
fmpz_poly_init(a);
fmpz_poly_init(b);
fmpz_poly_init(c);
fmpz_poly_randtest(b, state, n_randint(state, 40), 80);
fmpz_poly_randtest(c, state, n_randint(state, 40), 80);
d1 = fmpz_poly_gcd_heuristic(a, b, c);
d2 = fmpz_poly_gcd_heuristic(c, b, c);
result = ((d1 == 0 && d2 == 0) || (fmpz_poly_equal(a, c)
&& _t_gcd_is_canonical(a)));
if (!result)
{
flint_printf("FAIL (aliasing a and c):\n");
flint_printf("a = "), fmpz_poly_print(a), flint_printf("\n\n");
flint_printf("c = "), fmpz_poly_print(c), flint_printf("\n\n");
abort();
}
fmpz_poly_clear(a);
fmpz_poly_clear(b);
fmpz_poly_clear(c);
}
/* Check that a divides GCD(af, ag) */
for (i = 0; i < 300 * flint_test_multiplier(); i++)
{
fmpz_poly_t a, d, f, g, q, r;
fmpz_poly_init(a);
fmpz_poly_init(d);
fmpz_poly_init(f);
fmpz_poly_init(g);
fmpz_poly_init(q);
fmpz_poly_init(r);
fmpz_poly_randtest_not_zero(a, state, n_randint(state, 100) + 1, 40);
fmpz_poly_randtest(f, state, n_randint(state, 100), 40);
fmpz_poly_randtest(g, state, n_randint(state, 100), 40);
fmpz_poly_mul(f, a, f);
fmpz_poly_mul(g, a, g);
d1 = fmpz_poly_gcd_heuristic(d, f, g);
if (d1)
{
fmpz_poly_divrem_divconquer(q, r, d, a);
result = fmpz_poly_is_zero(r) && _t_gcd_is_canonical(d);
if (!result)
{
flint_printf("FAIL (check a | gcd(af, ag)):\n");
flint_printf("f = "), fmpz_poly_print(f), flint_printf("\n");
flint_printf("g = "), fmpz_poly_print(g), flint_printf("\n");
flint_printf("a = "), fmpz_poly_print(a), flint_printf("\n");
flint_printf("d = "), fmpz_poly_print(d), flint_printf("\n");
abort();
}
}
fmpz_poly_clear(a);
fmpz_poly_clear(d);
fmpz_poly_clear(f);
fmpz_poly_clear(g);
fmpz_poly_clear(q);
fmpz_poly_clear(r);
}
/* Check that a == GCD(af, ag) when GCD(f, g) = 1 */
for (i = 0; i < 300 * flint_test_multiplier(); i++)
{
fmpz_poly_t a, d, f, g, q, r;
fmpz_poly_init(a);
fmpz_poly_init(d);
fmpz_poly_init(f);
fmpz_poly_init(g);
fmpz_poly_init(q);
fmpz_poly_init(r);
fmpz_poly_randtest_not_zero(a, state, n_randint(state, 100) + 1, 200);
do {
fmpz_poly_randtest(f, state, n_randint(state, 100), 200);
fmpz_poly_randtest(g, state, n_randint(state, 100), 200);
fmpz_poly_gcd_heuristic(d, f, g);
} while (!(d->length == 1 && fmpz_is_one(d->coeffs)));
fmpz_poly_mul(f, a, f);
fmpz_poly_mul(g, a, g);
d1 = fmpz_poly_gcd_heuristic(d, f, g);
if (d1)
{
if (!_t_gcd_is_canonical(a)) fmpz_poly_neg(a, a);
result = fmpz_poly_equal(d, a) && _t_gcd_is_canonical(d);
if (!result)
{
flint_printf("FAIL (check a == gcd(af, ag) when gcd(f, g) = 1):\n");
flint_printf("f = "), fmpz_poly_print(f), flint_printf("\n");
flint_printf("g = "), fmpz_poly_print(g), flint_printf("\n");
flint_printf("a = "), fmpz_poly_print(a), flint_printf("\n");
flint_printf("d = "), fmpz_poly_print(d), flint_printf("\n");
abort();
}
}
fmpz_poly_clear(a);
fmpz_poly_clear(d);
fmpz_poly_clear(f);
fmpz_poly_clear(g);
fmpz_poly_clear(q);
fmpz_poly_clear(r);
}
/* Sebastian's test case */
{
fmpz_poly_t a, b, d;
fmpz_poly_init(a);
fmpz_poly_init(b);
fmpz_poly_init(d);
fmpz_poly_set_coeff_ui(b, 2, 1);
fmpz_poly_set_coeff_si(a, 0, -32);
fmpz_poly_set_coeff_si(a, 1, 24);
fmpz_poly_gcd_heuristic(d, a, b);
result = (d->length == 1 && fmpz_is_one(d->coeffs));
if (!result)
{
flint_printf("FAIL (check 1 == gcd(x^2, 24*x - 32):\n");
fmpz_poly_print(d); flint_printf("\n");
abort();
}
fmpz_poly_clear(a);
fmpz_poly_clear(b);
fmpz_poly_clear(d);
}
FLINT_TEST_CLEANUP(state);
flint_printf("PASS\n");
return 0;
}