arb/arb_hypgeom/rising_ui.c

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/*
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 "arb_hypgeom.h"
void
arb_hypgeom_rising_ui(arb_t y, const arb_t x, ulong n, slong prec)
{
if (n < FLINT_MAX(prec, 100))
{
arb_hypgeom_rising_ui_rec(y, x, n, prec);
}
else
{
arb_t t;
arb_init(t);
arb_add_ui(t, x, n, prec);
arb_gamma(t, t, prec);
arb_rgamma(y, x, prec);
arb_mul(y, y, t, prec);
arb_clear(t);
}
}
void
arb_hypgeom_rising(arb_t y, const arb_t x, const arb_t n, slong prec)
{
if (arb_is_int(n) && arf_sgn(arb_midref(n)) >= 0 &&
arf_cmpabs_ui(arb_midref(n), FLINT_MAX(prec, 100)) < 0)
{
arb_hypgeom_rising_ui_rec(y, x,
arf_get_si(arb_midref(n), ARF_RND_DOWN), prec);
}
else
{
arb_t t;
arb_init(t);
arb_add(t, x, n, prec);
arb_gamma(t, t, prec);
arb_rgamma(y, x, prec);
arb_mul(y, y, t, prec);
arb_clear(t);
}
}