arb/acb_modular/j.c
2016-04-26 17:20:05 +02:00

70 lines
1.6 KiB
C

/*
Copyright (C) 2014 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_modular.h"
void
acb_modular_j(acb_t z, const acb_t tau, slong prec)
{
psl2z_t g;
arf_t one_minus_eps;
acb_t tau_prime, t2, t3, t4, q;
psl2z_init(g);
arf_init(one_minus_eps);
acb_init(tau_prime);
acb_init(t2);
acb_init(t3);
acb_init(t4);
acb_init(q);
arf_set_ui_2exp_si(one_minus_eps, 63, -6);
acb_modular_fundamental_domain_approx(tau_prime, g, tau,
one_minus_eps, prec);
acb_exp_pi_i(q, tau_prime, prec);
acb_modular_theta_const_sum(t2, t3, t4, q, prec);
/* theta2 ^ 8 */
acb_mul(t2, t2, t2, prec);
acb_mul(t2, t2, t2, prec);
acb_mul(t2, t2, q, prec);
acb_mul(t2, t2, t2, prec);
/* theta3 ^ 8 */
acb_mul(t3, t3, t3, prec);
acb_mul(t3, t3, t3, prec);
acb_mul(t3, t3, t3, prec);
/* theta4 ^ 8 */
acb_mul(t4, t4, t4, prec);
acb_mul(t4, t4, t4, prec);
acb_mul(t4, t4, t4, prec);
acb_mul(z, t2, t3, prec);
acb_mul(z, z, t4, prec);
acb_add(t2, t2, t3, prec);
acb_add(t2, t2, t4, prec);
acb_cube(t2, t2, prec);
acb_div(z, t2, z, prec);
acb_mul_2exp_si(z, z, 5);
psl2z_clear(g);
arf_clear(one_minus_eps);
acb_clear(tau_prime);
acb_clear(t2);
acb_clear(t3);
acb_clear(t4);
acb_clear(q);
}