98 lines
2.7 KiB
C
98 lines
2.7 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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******************************************************************************/
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#define ulong ulongxx /* interferes with system includes */
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#include <stdlib.h>
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#undef ulong
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#define ulong mp_limb_t
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#include <gmp.h>
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#include "flint.h"
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#include "ulong_extras.h"
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#include "fmpz.h"
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void
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fmpz_root(fmpz_t r, const fmpz_t f, slong n)
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{
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fmpz c = *f;
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if (n == 0)
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{
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flint_printf("Exception (fmpz_root). Unable to take 0-th root.\n");
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abort();
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}
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if (n == 1)
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{
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fmpz_set(r, f);
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return;
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}
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if (!COEFF_IS_MPZ(c)) /* f is small */
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{
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if (n == 2)
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{
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if (c < WORD(0))
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{
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flint_printf("Exception (fmpz_root). Unable to take square root of negative value.\n");
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abort();
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}
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fmpz_set_ui(r, n_sqrt(c));
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} else /* n > 2 */
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{
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__mpz_struct mpz2;
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__mpz_struct * mpz1;
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mp_limb_t cval;
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if (c == 0)
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{
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fmpz_set_ui(r, 0);
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return;
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}
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mpz1 = _fmpz_promote(r);
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cval = FLINT_ABS(c);
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mpz2._mp_d = &cval; /* mock up an mpz */
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mpz2._mp_size = 1;
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if (c < WORD(0))
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mpz2._mp_size = -1;
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mpz2._mp_alloc = 1;
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mpz_root(mpz1, &mpz2, n);
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_fmpz_demote_val(r); /* root may be small */
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}
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} else /* f is large */
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{
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__mpz_struct * mpz2 = COEFF_TO_PTR(c);
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__mpz_struct * mpz1 = _fmpz_promote(r);
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mpz_root(mpz1, mpz2, n);
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_fmpz_demote_val(r); /* root may be small */
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}
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}
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