165 lines
5.5 KiB
C
165 lines
5.5 KiB
C
/*=============================================================================
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This file is part of FLINT.
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FLINT is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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FLINT is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with FLINT; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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=============================================================================*/
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/******************************************************************************
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Copyright (C) 2011 William Hart
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Copyright (C) 2011 Sebastian Pancratz
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******************************************************************************/
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#include <stdio.h>
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#include <stdlib.h>
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#include <gmp.h>
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#include "flint.h"
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#include "nmod_poly.h"
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#include "ulong_extras.h"
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#include "mpn_extras.h"
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#define __mul(C, lenC, A, lenA, B, lenB) \
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do { \
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if ((lenA) != 0 && (lenB) != 0) \
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{ \
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if ((lenA) >= (lenB)) \
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_nmod_poly_mul((C), (A), (lenA), (B), (lenB), mod); \
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else \
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_nmod_poly_mul((C), (B), (lenB), (A), (lenA), mod); \
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(lenC) = (lenA) + (lenB) - 1; \
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} \
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else \
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{ \
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(lenC) = 0; \
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} \
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} while (0)
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int
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main(void)
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{
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int i, result;
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FLINT_TEST_INIT(state);
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flint_printf("hgcd....");
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fflush(stdout);
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/*
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Find coprime polys, multiply by another poly
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and check the GCD is that poly
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*/
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for (i = 0; i < 100 * flint_test_multiplier(); i++)
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{
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nmod_poly_t a, b, c, d, c1, d1, s, t;
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mp_ptr M[4];
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slong lenM[4];
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slong sgnM;
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mp_limb_t n = n_randprime(state, FLINT_BITS, 0);
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nmod_poly_init(a, n);
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nmod_poly_init(b, n);
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nmod_poly_init(c, n);
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nmod_poly_init(d, n);
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nmod_poly_init(c1, n);
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nmod_poly_init(d1, n);
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nmod_poly_init(s, n);
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nmod_poly_init(t, n);
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do {
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nmod_poly_randtest_not_zero(a, state, n_randint(state, 800) + 1);
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nmod_poly_randtest_not_zero(b, state, n_randint(state, 800) + 1);
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} while (a->length == b->length);
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if (a->length < b->length)
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nmod_poly_swap(a, b);
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M[0] = _nmod_vec_init(a->length);
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M[1] = _nmod_vec_init(a->length);
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M[2] = _nmod_vec_init(a->length);
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M[3] = _nmod_vec_init(a->length);
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nmod_poly_fit_length(c, a->length);
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nmod_poly_fit_length(d, b->length);
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sgnM = _nmod_poly_hgcd(M, lenM,
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c->coeffs, &(c->length), d->coeffs, &(d->length),
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a->coeffs, a->length, b->coeffs, b->length, a->mod);
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nmod_poly_fit_length(s, 2 * a->length);
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nmod_poly_fit_length(t, 2 * a->length);
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/* [c1,d1] := sgnM * M^{-1} [a,b] */
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{
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const nmod_t mod = a->mod;
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MPN_SWAP(M[0], lenM[0], M[3], lenM[3]);
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_nmod_vec_neg(M[1], M[1], lenM[1], mod);
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_nmod_vec_neg(M[2], M[2], lenM[2], mod);
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__mul(s->coeffs, s->length, M[0], lenM[0], a->coeffs, a->length);
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__mul(t->coeffs, t->length, M[1], lenM[1], b->coeffs, b->length);
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nmod_poly_add(c1, s, t);
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__mul(s->coeffs, s->length, M[2], lenM[2], a->coeffs, a->length);
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__mul(t->coeffs, t->length, M[3], lenM[3], b->coeffs, b->length);
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nmod_poly_add(d1, s, t);
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}
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if (sgnM < 0)
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{
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nmod_poly_neg(c1, c1);
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nmod_poly_neg(d1, d1);
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}
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result = (nmod_poly_equal(c, c1) && nmod_poly_equal(d, d1));
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if (!result)
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{
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flint_printf("FAIL:\n");
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flint_printf("a = "), nmod_poly_print(a), flint_printf("\n\n");
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flint_printf("b = "), nmod_poly_print(b), flint_printf("\n\n");
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flint_printf("c = "), nmod_poly_print(c), flint_printf("\n\n");
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flint_printf("d = "), nmod_poly_print(d), flint_printf("\n\n");
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flint_printf("c1 = "), nmod_poly_print(c1), flint_printf("\n\n");
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flint_printf("d1 = "), nmod_poly_print(d1), flint_printf("\n\n");
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abort();
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}
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nmod_poly_clear(a);
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nmod_poly_clear(b);
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nmod_poly_clear(c);
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nmod_poly_clear(d);
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nmod_poly_clear(c1);
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nmod_poly_clear(d1);
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nmod_poly_clear(s);
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nmod_poly_clear(t);
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_nmod_vec_clear(M[0]);
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_nmod_vec_clear(M[1]);
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_nmod_vec_clear(M[2]);
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_nmod_vec_clear(M[3]);
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}
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FLINT_TEST_CLEANUP(state);
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flint_printf("PASS\n");
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return 0;
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}
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#undef __mul
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