arb/acb_hypgeom/erfc.c
2015-01-21 17:28:16 +01:00

57 lines
1.7 KiB
C

/*=============================================================================
This file is part of ARB.
ARB is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
ARB is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with ARB; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2015 Fredrik Johansson
******************************************************************************/
#include "acb_hypgeom.h"
void
acb_hypgeom_erfc(acb_t res, const acb_t z, long prec)
{
if (arb_is_positive(acb_realref(z)))
{
acb_t t, u;
acb_init(t);
acb_init(u);
acb_set_si(t, 1);
acb_mul_2exp_si(t, t, -1);
acb_mul(u, z, z, prec);
acb_hypgeom_gamma_upper(res, t, u, 0, prec);
arb_const_sqrt_pi(acb_realref(t), prec);
acb_div_arb(res, res, acb_realref(t), prec);
acb_clear(t);
acb_clear(u);
}
else
{
acb_hypgeom_erf(res, z, prec);
acb_sub_ui(res, res, 1, prec);
acb_neg(res, res);
}
}