mirror of
https://github.com/vale981/arb
synced 2025-03-05 09:21:38 -05:00
52 lines
1.2 KiB
C
52 lines
1.2 KiB
C
/*
|
|
Copyright (C) 2015 Fredrik Johansson
|
|
|
|
This file is part of Arb.
|
|
|
|
Arb is free software: you can redistribute it and/or modify it under
|
|
the terms of the GNU Lesser General Public License (LGPL) as published
|
|
by the Free Software Foundation; either version 2.1 of the License, or
|
|
(at your option) any later version. See <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include "acb.h"
|
|
|
|
void
|
|
acb_quadratic_roots_fmpz(acb_t r1, acb_t r2,
|
|
const fmpz_t a, const fmpz_t b, const fmpz_t c, slong prec)
|
|
{
|
|
fmpz_t d;
|
|
fmpz_init(d);
|
|
|
|
/* d = b^2 - 4ac */
|
|
fmpz_mul(d, a, c);
|
|
fmpz_mul_2exp(d, d, 2);
|
|
fmpz_submul(d, b, b);
|
|
fmpz_neg(d, d);
|
|
|
|
/* +/- sqrt(d) */
|
|
acb_zero(r1);
|
|
if (fmpz_sgn(d) >= 0)
|
|
{
|
|
arb_sqrt_fmpz(acb_realref(r1), d, prec + fmpz_bits(d) + 4);
|
|
}
|
|
else
|
|
{
|
|
fmpz_neg(d, d);
|
|
arb_sqrt_fmpz(acb_imagref(r1), d, prec + fmpz_bits(d) + 4);
|
|
}
|
|
acb_neg(r2, r1);
|
|
|
|
/* -b */
|
|
acb_sub_fmpz(r1, r1, b, prec + 4);
|
|
acb_sub_fmpz(r2, r2, b, prec + 4);
|
|
|
|
/* divide by 2a */
|
|
fmpz_mul_2exp(d, a, 1);
|
|
acb_div_fmpz(r1, r1, d, prec);
|
|
acb_div_fmpz(r2, r2, d, prec);
|
|
|
|
fmpz_clear(d);
|
|
return;
|
|
}
|
|
|