arb/arb_hypgeom/test/t-legendre_p_ui_asymp.c

114 lines
3.6 KiB
C

/*
Copyright (C) 2017 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"
int main()
{
slong iter;
flint_rand_t state;
flint_printf("legendre_p_ui_asymp....");
fflush(stdout);
flint_randinit(state);
for (iter = 0; iter < 2000 * arb_test_multiplier(); iter++)
{
arb_t x, r1, r1p, r2, r2p, r3, s;
ulong n;
slong prec1, prec2, K, K2, K3;
arb_init(x);
arb_init(r1);
arb_init(r1p);
arb_init(r2);
arb_init(r2p);
arb_init(r3);
arb_init(s);
n = n_randtest(state) % 500;
K = n_randint(state, 50);
K2 = n_randint(state, 500);
prec1 = 2 + n_randint(state, 1000);
prec2 = 2 + n_randint(state, 500);
arb_randtest(x, state, 2 + n_randint(state, 1000), 0);
arb_mul_2exp_si(x, x, -n_randint(state, 8));
if (n_randint(state, 2))
mag_zero(arb_radref(x));
arb_hypgeom_legendre_p_ui_asymp(r1, r1p, n, x, K, prec1);
arb_hypgeom_legendre_p_ui_one(r2, r2p, n, x, K2, prec2);
if (!arb_overlaps(r1, r2) || !arb_overlaps(r1p, r2p))
{
flint_printf("FAIL: overlap\n\n");
flint_printf("n = %wu, K = %wd\n\n", n, K);
flint_printf("x = "); arb_printn(x, 50, 0); flint_printf("\n\n");
flint_printf("r1 = "); arb_printn(r1, 50, 0); flint_printf("\n\n");
flint_printf("r2 = "); arb_printn(r2, 50, 0); flint_printf("\n\n");
flint_printf("r1p = "); arb_printn(r1p, 50, 0); flint_printf("\n\n");
flint_printf("r2p = "); arb_printn(r2p, 50, 0); flint_printf("\n\n");
flint_abort();
}
n = n_randtest(state);
if (n == UWORD_MAX) n--;
if (n == 0) n++;
K = n_randint(state, 50);
K2 = n_randint(state, 50);
K3 = n_randint(state, 50);
/* test (2n+1) x P_n(x) - n P_(n-1)(x) = (n+1) P_(n+1)(x) */
arb_hypgeom_legendre_p_ui_asymp(r1, NULL, n, x, K, prec2);
arb_mul(r1, r1, x, prec2);
arb_set_ui(r2, n);
arb_add_ui(r2, r2, n, prec2);
arb_add_ui(r2, r2, 1, prec2);
arb_mul(r1, r1, r2, prec2);
arb_hypgeom_legendre_p_ui_asymp(r2, NULL, n - 1, x, K2, prec2);
arb_mul_ui(r2, r2, n, prec2);
arb_hypgeom_legendre_p_ui_asymp(r3, NULL, n + 1, x, K3, prec2);
arb_mul_ui(r3, r3, n + 1, prec2);
arb_sub(s, r1, r2, prec2);
if (!arb_overlaps(s, r3))
{
flint_printf("FAIL: overlap (2)\n\n");
flint_printf("n = %wu, K = %wd, K2 = %wd, K3 = %wd\n\n", n, K, K2, K3);
flint_printf("x = "); arb_printn(x, 50, 0); flint_printf("\n\n");
flint_printf("r1 = "); arb_printn(r1, 50, 0); flint_printf("\n\n");
flint_printf("r2 = "); arb_printn(r2, 50, 0); flint_printf("\n\n");
flint_printf("s = "); arb_printn(s, 50, 0); flint_printf("\n\n");
flint_printf("r3 = "); arb_printn(r3, 50, 0); flint_printf("\n\n");
flint_abort();
}
arb_clear(x);
arb_clear(r1);
arb_clear(r1p);
arb_clear(r2);
arb_clear(r2p);
arb_clear(r3);
arb_clear(s);
}
flint_randclear(state);
flint_cleanup();
flint_printf("PASS\n");
return EXIT_SUCCESS;
}