mirror of
https://github.com/vale981/arb
synced 2025-03-04 17:01:40 -05:00
44 lines
1 KiB
C
44 lines
1 KiB
C
/*
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Copyright (C) 2015 Fredrik Johansson
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This file is part of Arb.
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Arb is free software: you can redistribute it and/or modify it under
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the terms of the GNU Lesser General Public License (LGPL) as published
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by the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version. See <http://www.gnu.org/licenses/>.
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*/
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#include "acb.h"
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void
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acb_acos(acb_t res, const acb_t z, slong prec)
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{
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if (acb_is_one(z))
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{
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acb_zero(res);
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}
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else
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{
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acb_t t;
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acb_init(t);
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acb_one(t);
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if (arb_is_zero(acb_imagref(z))
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&& arb_gt(acb_realref(z), acb_realref(t)))
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{
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/* pure imaginary on (1,inf) */
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acb_asin(res, z, prec);
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acb_neg(res, res);
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arb_zero(acb_realref(res));
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}
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else
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{
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acb_asin(res, z, prec);
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acb_const_pi(t, prec);
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acb_mul_2exp_si(t, t, -1);
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acb_sub(res, t, res, prec);
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}
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acb_clear(t);
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}
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}
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