1/* tj1 -- test file for the Bessel function of first kind (order 1)
2
3Copyright 2007-2023 Free Software Foundation, Inc.
4Contributed by the AriC and Caramba projects, INRIA.
5
6This file is part of the GNU MPFR Library.
7
8The GNU MPFR Library is free software; you can redistribute it and/or modify
9it under the terms of the GNU Lesser General Public License as published by
10the Free Software Foundation; either version 3 of the License, or (at your
11option) any later version.
12
13The GNU MPFR Library is distributed in the hope that it will be useful, but
14WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
16License for more details.
17
18You should have received a copy of the GNU Lesser General Public License
19along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
20https://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
2151 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
22
23#include "mpfr-test.h"
24
25#define TEST_FUNCTION mpfr_j1
26#define RAND_FUNCTION(x) mpfr_random2(x, MPFR_LIMB_SIZE (x), 8, RANDS)
27#define REDUCE_EMAX 262143 /* otherwise arg. reduction is too expensive */
28#include "tgeneric.c"
29
30/* test for small input, where j1(x) = x/2 - x^3/16 + ... */
31static void
32test_small (void)
33{
34  mpfr_t x, y;
35  int inex, sign;
36  mpfr_exp_t e, emin;
37
38  mpfr_init2 (x, 10);
39  mpfr_init2 (y, 9);
40  emin = mpfr_get_emin ();
41  for (e = -4; e >= -30; e--)
42    {
43      if (e == -30)
44        {
45          e = mpfr_get_emin_min () - 1;
46          set_emin (e + 1);
47        }
48      for (sign = -1; sign <= 1; sign += 2)
49        {
50          mpfr_set_si_2exp (x, sign, e, MPFR_RNDN);
51          mpfr_nexttoinf (x);
52          inex = mpfr_j1 (y, x, MPFR_RNDN);
53          if (e >= -29)
54            {
55              /* since |x| is just above 2^e, |j1(x)| is just above 2^(e-1),
56                 thus y should be 2^(e-1) and the inexact flag should be
57                 of opposite sign of x */
58              MPFR_ASSERTN(mpfr_cmp_si_2exp0 (y, sign, e - 1) == 0);
59              MPFR_ASSERTN(VSIGN (inex) * sign < 0);
60            }
61          else
62            {
63              /* here |y| should be 0.5*2^emin and the inexact flag should
64                 have the sign of x */
65              MPFR_ASSERTN(mpfr_cmp_si_2exp0 (y, sign, e) == 0);
66              MPFR_ASSERTN(VSIGN (inex) * sign > 0);
67            }
68        }
69    }
70  set_emin (emin);
71  mpfr_clear (x);
72  mpfr_clear (y);
73}
74
75/* a test that fails with GMP_CHECK_RANDOMIZE=1613146232984428
76   on revision 14429 */
77static void
78bug20210215 (void)
79{
80  mpfr_t x, y;
81  int inex;
82
83  mpfr_init2 (x, 221);
84  mpfr_init2 (y, 1);
85  mpfr_set_str (x, "1.6484611511696130037307738844228498447763863563070374544054791168614e+01", 10, MPFR_RNDN);
86  mpfr_clear_flags ();
87  inex = mpfr_j1 (y, x, MPFR_RNDZ);
88  MPFR_ASSERTN (mpfr_cmp_si_2exp0 (y, -1, -9) == 0);
89  MPFR_ASSERTN (inex > 0);
90  MPFR_ASSERTN (__gmpfr_flags == MPFR_FLAGS_INEXACT);
91  mpfr_clear (x);
92  mpfr_clear (y);
93}
94
95int
96main (int argc, char *argv[])
97{
98  mpfr_t x, y;
99
100  tests_start_mpfr ();
101
102  bug20210215 ();
103
104  test_small ();
105
106  mpfr_init (x);
107  mpfr_init (y);
108
109  /* special values */
110  mpfr_set_nan (x);
111  mpfr_j1 (y, x, MPFR_RNDN);
112  MPFR_ASSERTN(mpfr_nan_p (y));
113
114  mpfr_set_inf (x, 1); /* +Inf */
115  mpfr_j1 (y, x, MPFR_RNDN);
116  MPFR_ASSERTN(mpfr_cmp_ui (y, 0) == 0 && MPFR_IS_POS (y));
117
118  mpfr_set_inf (x, -1); /* -Inf */
119  mpfr_j1 (y, x, MPFR_RNDN);
120  MPFR_ASSERTN(mpfr_cmp_ui (y, 0) == 0 && MPFR_IS_POS (y));
121
122  mpfr_set_ui (x, 0, MPFR_RNDN); /* +0 */
123  mpfr_j1 (y, x, MPFR_RNDN);
124  MPFR_ASSERTN(mpfr_cmp_ui (y, 0) == 0 && MPFR_IS_POS (y)); /* j1(+0)=+0 */
125
126  mpfr_set_ui (x, 0, MPFR_RNDN);
127  mpfr_neg (x, x, MPFR_RNDN); /* -0 */
128  mpfr_j1 (y, x, MPFR_RNDN);
129  MPFR_ASSERTN(mpfr_cmp_ui (y, 0) == 0 && MPFR_IS_NEG (y)); /* j1(-0)=-0 */
130
131  mpfr_set_prec (x, 53);
132  mpfr_set_prec (y, 53);
133
134  mpfr_set_ui (x, 1, MPFR_RNDN);
135  mpfr_j1 (y, x, MPFR_RNDN);
136  mpfr_set_str_binary (x, "0.0111000010100111001001111011101001011100001100011011");
137  if (mpfr_cmp (x, y))
138    {
139      printf ("Error in mpfr_j1 for x=1, rnd=MPFR_RNDN\n");
140      printf ("Expected "); mpfr_dump (x);
141      printf ("Got      "); mpfr_dump (y);
142      exit (1);
143    }
144  mpfr_clear (x);
145  mpfr_clear (y);
146
147  test_generic (MPFR_PREC_MIN, 100, 10);
148
149  data_check ("data/j1", mpfr_j1, "mpfr_j1");
150
151  tests_end_mpfr ();
152
153  return 0;
154}
155