mirror of
https://github.com/vale981/arb
synced 2025-03-05 09:21:38 -05:00
69 lines
1.4 KiB
C
69 lines
1.4 KiB
C
/*
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Copyright (C) 2021 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 "arb_hypgeom.h"
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static void
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bsplit(arb_t y, const arb_t x, ulong a, ulong b, slong prec)
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{
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if (b - a <= 16)
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{
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if (a == 0)
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{
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arb_hypgeom_rising_ui_forward(y, x, b, prec);
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}
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else
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{
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arb_add_ui(y, x, a, prec);
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arb_hypgeom_rising_ui_forward(y, y, b - a, prec);
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}
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}
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else
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{
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arb_t t, u;
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ulong m = a + (b - a) / 2;
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arb_init(t);
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arb_init(u);
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bsplit(t, x, a, m, prec);
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bsplit(u, x, m, b, prec);
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arb_mul(y, t, u, prec);
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arb_clear(t);
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arb_clear(u);
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}
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}
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void
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arb_hypgeom_rising_ui_bs(arb_t res, const arb_t x, ulong n, slong prec)
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{
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if (n <= 1)
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{
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if (n == 0)
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arb_one(res);
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else
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arb_set_round(res, x, prec);
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return;
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}
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{
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arb_t t;
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slong wp = ARF_PREC_ADD(prec, FLINT_BIT_COUNT(n));
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arb_init(t);
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bsplit(t, x, 0, n, wp);
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arb_set_round(res, t, prec);
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arb_clear(t);
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}
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}
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