arb/acb_modular/elliptic_k.c

42 lines
1.4 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) 2014 Fredrik Johansson
******************************************************************************/
#include "acb_modular.h"
void
acb_modular_elliptic_k(acb_t k, const acb_t m, slong prec)
{
acb_t t;
acb_init(t);
acb_sub_ui(t, m, 1, prec);
acb_neg(t, t);
acb_sqrt(t, t, prec);
acb_agm1(k, t, prec);
acb_const_pi(t, prec);
acb_div(k, t, k, prec);
acb_mul_2exp_si(k, k, -1);
acb_clear(t);
}