1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
/*
Copyright (C) 2023 Jean Kieffer
This file is part of FLINT.
FLINT 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 3 of the License, or
(at your option) any later version. See <https://www.gnu.org/licenses/>.
*/
#include "acb.h"
#include "acb_theta.h"
void
acb_theta_g2_chi5(acb_t res, acb_srcptr th, slong prec)
{
slong g = 2;
slong n = 1 << (2 * g);
ulong ab;
acb_t t;
acb_init(t);
acb_one(t);
for (ab = 0; ab < n; ab++)
{
if (acb_theta_char_is_even(ab, g))
{
acb_mul(t, t, &th[ab], prec);
}
}
acb_neg(res, t);
acb_mul_2exp_si(res, res, -6);
acb_clear(t);
}