pqc/external/flint-2.4.3/fmpz_poly/test/t-hensel_lift.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 William Hart
Copyright (C) 2011 Sebastian Pancratz
******************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <gmp.h>
#include "flint.h"
#include "fmpz.h"
#include "fmpz_poly.h"
#include "nmod_poly.h"
#include "ulong_extras.h"
int
main(void)
{
int i, result;
FLINT_TEST_INIT(state);
flint_printf("hensel_lift....");
fflush(stdout);
/* We check that lifting local factors of F_poly yields factors */
for (i = 0; i < 100 * flint_test_multiplier(); i++)
{
fmpz_poly_t F_poly, F_poly2, F_poly3, A, B, G, H,
A_out, B_out, G_out, H_out, Prod_1, Prod_2;
nmod_poly_t a, b, d, g, h, prod;
fmpz_t p, p1, big_P, p1_2, big_P_2;
slong bits, length, nbits, n, exp, part_exp;
bits = n_randint(state, 200) + 1;
nbits = n_randint(state, FLINT_BITS - 6) + 6;
fmpz_init(p);
fmpz_init(p1);
fmpz_init(big_P);
fmpz_init(p1_2);
fmpz_init(big_P_2);
fmpz_poly_init(F_poly);
fmpz_poly_init(F_poly2);
fmpz_poly_init(F_poly3);
fmpz_poly_init(Prod_1);
fmpz_poly_init(Prod_2);
fmpz_poly_init(A);
fmpz_poly_init(B);
fmpz_poly_init(G);
fmpz_poly_init(H);
fmpz_poly_init(A_out);
fmpz_poly_init(B_out);
fmpz_poly_init(G_out);
fmpz_poly_init(H_out);
n = n_randprime(state, nbits, 0);
exp = bits/(FLINT_BIT_COUNT(n) - 1) + 1;
part_exp = n_randint(state, exp);
nmod_poly_init(g, n);
nmod_poly_init(h, n);
nmod_poly_init(a, n);
nmod_poly_init(b, n);
nmod_poly_init(d, n);
nmod_poly_init(prod, n);
do {
length = n_randint(state, 200) + 2;
do { fmpz_poly_randtest(F_poly2, state, length, bits); }
while (F_poly2->length < 2);
fmpz_set_ui(F_poly2->coeffs, n_randbits(state, FLINT_MIN(bits, FLINT_BITS - 2)));
fmpz_set_ui(F_poly2->coeffs + F_poly2->length - 1, 1);
length = n_randint(state, 200) + 2;
do { fmpz_poly_randtest(F_poly3, state, length, bits); }
while (F_poly3->length < 2);
fmpz_set_ui(F_poly3->coeffs, n_randbits(state, FLINT_MIN(bits, FLINT_BITS - 2)));
fmpz_set_ui(F_poly3->coeffs + F_poly3->length - 1, 1);
fmpz_poly_mul(F_poly, F_poly2, F_poly3);
fmpz_poly_get_nmod_poly(prod, F_poly);
} while (!nmod_poly_is_squarefree(prod));
fmpz_poly_get_nmod_poly(g, F_poly2);
fmpz_poly_get_nmod_poly(h, F_poly3);
nmod_poly_xgcd(d, a, b, g, h);
nmod_poly_clear(prod);
nmod_poly_clear(d);
fmpz_poly_set_nmod_poly(A, a);
fmpz_poly_set_nmod_poly(B, b);
fmpz_poly_set_nmod_poly(G, g);
fmpz_poly_set_nmod_poly(H, h);
fmpz_set_ui(p, n);
fmpz_set_ui(p1, n);
fmpz_set_ui(big_P, n);
fmpz_set_ui(p1_2, n);
fmpz_set_ui(big_P_2, n);
part_exp = 1;
while (part_exp < exp)
{
fmpz_set(p, big_P);
fmpz_set_ui(p1, n);
fmpz_set_ui(big_P, n);
if (exp - part_exp <= part_exp)
{
fmpz_pow_ui(p1, p1, exp - part_exp);
fmpz_pow_ui(big_P, big_P, exp);
part_exp = exp;
}
else
{
fmpz_set(p1, p);
fmpz_pow_ui(big_P, big_P, 2*part_exp);
part_exp = 2*part_exp;
}
fmpz_poly_hensel_lift(G_out, H_out, A_out, B_out, F_poly,
G, H, A, B, p, p1);
fmpz_poly_set(G, G_out);
fmpz_poly_set(H, H_out);
fmpz_poly_set(A, A_out);
fmpz_poly_set(B, B_out);
}
fmpz_poly_mul(Prod_1, A, G);
fmpz_poly_mul(Prod_2, B, H);
fmpz_poly_add(Prod_1, Prod_1, Prod_2);
fmpz_poly_scalar_smod_fmpz(Prod_1, Prod_1, big_P);
result = (Prod_1->length == 1 && fmpz_is_one(Prod_1->coeffs));
if (!result)
{
flint_printf("FAIL:\n");
flint_printf("length = %wd, bits = %wd, n = %wd, exp = %wd\n", length, bits, n, exp);
fmpz_poly_print(F_poly); flint_printf("\n\n");
fmpz_poly_print(F_poly2); flint_printf("\n\n");
fmpz_poly_print(F_poly3); flint_printf("\n\n");
fmpz_poly_print(Prod_1); flint_printf("\n\n");
abort();
}
nmod_poly_clear(g);
nmod_poly_clear(h);
nmod_poly_clear(a);
nmod_poly_clear(b);
fmpz_poly_clear(Prod_1);
fmpz_poly_clear(Prod_2);
fmpz_poly_clear(A);
fmpz_poly_clear(B);
fmpz_poly_clear(G);
fmpz_poly_clear(H);
fmpz_poly_clear(A_out);
fmpz_poly_clear(B_out);
fmpz_poly_clear(G_out);
fmpz_poly_clear(H_out);
fmpz_clear(p);
fmpz_clear(p1);
fmpz_clear(big_P);
fmpz_clear(p1_2);
fmpz_clear(big_P_2);
fmpz_poly_clear(F_poly3);
fmpz_poly_clear(F_poly2);
fmpz_poly_clear(F_poly);
}
FLINT_TEST_CLEANUP(state);
flint_printf("PASS\n");
return 0;
}