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/*
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_agm_hadamard(acb_ptr res, acb_srcptr a, slong g, slong prec)
{
acb_ptr v;
slong half;
if (g == 0)
{
acb_set(&res[0], &a[0]);
}
else
{
half = 1 << (g - 1);
v = _acb_vec_init(1 << g);
acb_theta_agm_hadamard(v, a, g - 1, prec);
acb_theta_agm_hadamard(v + half, a + half, g - 1, prec);
_acb_vec_add(res, v, v + half, half, prec);
_acb_vec_sub(res + half, v, v + half, half, prec);
_acb_vec_clear(v, 1 << g);
}
}