mirror of
https://github.com/vale981/arb
synced 2025-03-06 09:51:39 -05:00
66 lines
1.9 KiB
C
66 lines
1.9 KiB
C
/*=============================================================================
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This file is part of ARB.
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ARB 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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ARB 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 ARB; 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) 2015 Fredrik Johansson
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******************************************************************************/
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#include "acb.h"
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void
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acb_quadratic_roots_fmpz(acb_t r1, acb_t r2,
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const fmpz_t a, const fmpz_t b, const fmpz_t c, slong prec)
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{
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fmpz_t d;
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fmpz_init(d);
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/* d = b^2 - 4ac */
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fmpz_mul(d, a, c);
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fmpz_mul_2exp(d, d, 2);
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fmpz_submul(d, b, b);
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fmpz_neg(d, d);
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/* +/- sqrt(d) */
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acb_zero(r1);
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if (fmpz_sgn(d) >= 0)
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{
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arb_sqrt_fmpz(acb_realref(r1), d, prec + fmpz_bits(d) + 4);
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}
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else
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{
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fmpz_neg(d, d);
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arb_sqrt_fmpz(acb_imagref(r1), d, prec + fmpz_bits(d) + 4);
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}
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acb_neg(r2, r1);
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/* -b */
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acb_sub_fmpz(r1, r1, b, prec + 4);
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acb_sub_fmpz(r2, r2, b, prec + 4);
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/* divide by 2a */
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fmpz_mul_2exp(d, a, 1);
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acb_div_fmpz(r1, r1, d, prec);
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acb_div_fmpz(r2, r2, d, prec);
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fmpz_clear(d);
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return;
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}
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