122 lines
3.6 KiB
C
122 lines
3.6 KiB
C
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/*=============================================================================
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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 Fredrik Johansson
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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 "fmpz.h"
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#include "fmpq.h"
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#include "profiler.h"
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int
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main(void)
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{
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int i;
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FLINT_TEST_INIT(state);
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flint_printf("reconstruct_fmpz....");
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fflush(stdout);
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for (i = 0; i < 10000; i++)
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{
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int result;
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int modresult;
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int special_case;
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fmpq_t x, y;
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fmpz_t mod;
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fmpz_t res;
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mpz_t tmp;
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fmpq_init(x);
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fmpq_init(y);
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fmpz_init(mod);
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fmpz_init(res);
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mpz_init(tmp);
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fmpq_randtest(x, state, 100);
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/* Modulus m >= 2*max(|n|,d)^2 */
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if (fmpz_cmpabs(&x->num, &x->den) >= 0)
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fmpz_mul(mod, &x->num, &x->num);
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else
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fmpz_mul(mod, &x->den, &x->den);
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fmpz_mul_2exp(mod, mod, 1);
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/* Next prime greater than or equal */
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fmpz_get_mpz(tmp, mod);
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flint_mpz_sub_ui(tmp, tmp, UWORD(1));
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mpz_nextprime(tmp, tmp);
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fmpz_set_mpz(mod, tmp);
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modresult = fmpq_mod_fmpz(res, x, mod);
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result = fmpq_reconstruct_fmpz(y, res, mod);
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/* Special case: both 1 and -1 have residue 1 mod 2.
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There's probably no particular reason to disallow this. */
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special_case = (fmpz_cmp_ui(mod, UWORD(2)) == 0 &&
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fmpz_get_si(&x->num) == WORD(-1) &&
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fmpz_cmp_ui(&x->den, UWORD(1)) == 0);
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if (special_case)
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{
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if (!modresult || !result ||
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!fmpz_is_one(&y->num) || !fmpz_is_one(&y->den))
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{
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flint_printf("FAIL: special case: -1 mod 2\n");
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abort();
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}
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}
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else if (!modresult || !result || !fmpq_equal(x, y))
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{
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flint_printf("FAIL: reconstruction failed\n");
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flint_printf("input = ");
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fmpq_print(x);
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flint_printf("\nmodulus = ");
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fmpz_print(mod);
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flint_printf("\nresidue = ");
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fmpz_print(res);
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flint_printf("\nreconstructed = ");
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fmpq_print(y);
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flint_printf("\nfmpq_mod_fmpz return value = %d", modresult);
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flint_printf("\nfmpq_reconstruct_fmpz return value = %d", result);
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flint_printf("\n");
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abort();
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}
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fmpq_clear(x);
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fmpq_clear(y);
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fmpz_clear(mod);
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fmpz_clear(res);
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mpz_clear(tmp);
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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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