1 /* Test file for mpfr_tan.
2
3 Copyright 2001-2004, 2006-2023 Free Software Foundation, Inc.
4 Contributed by the AriC and Caramba projects, INRIA.
5
6 This file is part of the GNU MPFR Library.
7
8 The GNU MPFR Library is free software; you can redistribute it and/or modify
9 it under the terms of the GNU Lesser General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or (at your
11 option) any later version.
12
13 The GNU MPFR Library is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
16 License for more details.
17
18 You should have received a copy of the GNU Lesser General Public License
19 along with the GNU MPFR Library; see the file COPYING.LESSER. If not, see
20 https://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
21 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
22
23 #include "mpfr-test.h"
24
25 #define TEST_FUNCTION mpfr_tan
26 #define REDUCE_EMAX 262143 /* otherwise arg. reduction is too expensive */
27 #include "tgeneric.c"
28
29 static void
30 check_nans (void)
31 {
32 mpfr_t x, y;
33
34 mpfr_init2 (x, 123L);
35 mpfr_init2 (y, 123L);
36
37 mpfr_set_nan (x);
38 mpfr_tan (y, x, MPFR_RNDN);
39 if (! mpfr_nan_p (y))
40 {
41 printf ("Error: tan(NaN) != NaN\n");
42 exit (1);
43 }
44
45 mpfr_set_inf (x, 1);
46 mpfr_tan (y, x, MPFR_RNDN);
47 if (! mpfr_nan_p (y))
48 {
49 printf ("Error: tan(Inf) != NaN\n");
50 exit (1);
51 }
52
53 mpfr_set_inf (x, -1);
54 mpfr_tan (y, x, MPFR_RNDN);
55 if (! mpfr_nan_p (y))
56 {
57 printf ("Error: tan(-Inf) != NaN\n");
58 exit (1);
59 }
60
61 /* exercise recomputation */
62 mpfr_set_prec (x, 14);
63 mpfr_set_str_binary (x, "0.10100000101010E0");
64 mpfr_set_prec (y, 24);
65 mpfr_tan (y, x, MPFR_RNDU);
66 mpfr_set_prec (x, 24);
67 mpfr_set_str_binary (x, "101110011011001100100001E-24");
68 MPFR_ASSERTN(mpfr_cmp (x, y) == 0);
69
70 /* Compute ~Pi/2 to check overflow */
71 mpfr_set_prec (x, 20000);
72 mpfr_const_pi (x, MPFR_RNDD);
73 mpfr_div_2ui (x, x, 1, MPFR_RNDN);
74 mpfr_set_prec (y, 24);
75 mpfr_tan (y, x, MPFR_RNDN);
76 if (mpfr_cmp_str (y, "0.100011101101011000100011E20001", 2, MPFR_RNDN))
77 {
78 printf("Error computing tan(~Pi/2)\n");
79 mpfr_dump (y);
80 exit (1);
81 }
82
83 /* bug found by Kaveh Ghazi on 13 Jul 2007 */
84 mpfr_set_prec (x, 53);
85 mpfr_set_prec (y, 53);
86 mpfr_set_str_binary (x, "0.10011100110111000001000010110100101000000000000000000E34");
87 mpfr_tan (y, x, MPFR_RNDN);
88 mpfr_set_str_binary (x, "0.1000010011001010001000010100000110100111000011010101E41");
89 MPFR_ASSERTN(mpfr_cmp (x, y) == 0);
90
91 mpfr_clear (x);
92 mpfr_clear (y);
93 }
94
95 /* This test was generated from bad_cases, with GMP_CHECK_RANDOMIZE=1514257254.
96 For the x value below, we have tan(x) = -1.875 + epsilon,
97 thus with RNDZ it should be rounded to -1.c. */
98 static void
99 bug20171218 (void)
100 {
101 mpfr_t x, y, z;
102 mpfr_init2 (x, 804);
103 mpfr_init2 (y, 4);
104 mpfr_init2 (z, 4);
105 mpfr_set_str (x, "-1.14b1dd5f90ce0eded2a8f59c05e72daf7cc4c78f5075d73246fa420e2c026291d9377e67e7f54e925c4aed39c7b2f917424033c8612f00a19821890558d6c2cef9c60f4ad2c3b061ed53a1709dc1ec8e139627c2119c36d7ebdff0d715e559b47f740c534", 16, MPFR_RNDN);
106 mpfr_tan (y, x, MPFR_RNDZ);
107 mpfr_set_str (z, "-1.c", 16, MPFR_RNDN);
108 MPFR_ASSERTN(mpfr_equal_p (y, z));
109 mpfr_clear (x);
110 mpfr_clear (y);
111 mpfr_clear (z);
112 }
113
114 static void
115 coverage (void)
116 {
117 mpfr_t x, y;
118 int inex;
119 mpfr_exp_t emax;
120
121 /* exercise mpfr_round_near_x when rounding gives an overflow */
122 emax = mpfr_get_emax ();
123 set_emax (-2);
124 mpfr_init2 (x, 2);
125 mpfr_init2 (y, 2);
126 mpfr_setmax (x, mpfr_get_emax ());
127 inex = mpfr_tan (y, x, MPFR_RNDA);
128 MPFR_ASSERTN(inex > 0);
129 MPFR_ASSERTN(mpfr_inf_p (y) && mpfr_signbit (y) == 0);
130 mpfr_clear (x);
131 mpfr_clear (y);
132 set_emax (emax);
133 }
134
135 int
136 main (int argc, char *argv[])
137 {
138 mpfr_t x;
139 unsigned int i;
140 unsigned int prec[10] = {14, 15, 19, 22, 23, 24, 25, 40, 41, 52};
141 unsigned int prec2[10] = {4, 5, 6, 19, 70, 95, 100, 106, 107, 108};
142
143 tests_start_mpfr ();
144
145 coverage ();
146 bug20171218 ();
147 check_nans ();
148
149 mpfr_init (x);
150
151 mpfr_set_prec (x, 2);
152 mpfr_set_str (x, "0.5", 10, MPFR_RNDN);
153 mpfr_tan (x, x, MPFR_RNDD);
154 if (mpfr_cmp_ui_2exp(x, 1, -1))
155 {
156 printf ("mpfr_tan(0.5, MPFR_RNDD) failed\n"
157 "expected 0.5, got ");
158 mpfr_dump (x);
159 exit (1);
160 }
161
162 /* check that tan(3*Pi/4) ~ -1 */
163 for (i=0; i<10; i++)
164 {
165 mpfr_set_prec (x, prec[i]);
166 mpfr_const_pi (x, MPFR_RNDN);
167 mpfr_mul_ui (x, x, 3, MPFR_RNDN);
168 mpfr_div_ui (x, x, 4, MPFR_RNDN);
169 mpfr_tan (x, x, MPFR_RNDN);
170 if (mpfr_cmp_si (x, -1))
171 {
172 printf ("tan(3*Pi/4) fails for prec=%u\n", prec[i]);
173 exit (1);
174 }
175 }
176
177 /* check that tan(7*Pi/4) ~ -1 */
178 for (i=0; i<10; i++)
179 {
180 mpfr_set_prec (x, prec2[i]);
181 mpfr_const_pi (x, MPFR_RNDN);
182 mpfr_mul_ui (x, x, 7, MPFR_RNDN);
183 mpfr_div_ui (x, x, 4, MPFR_RNDN);
184 mpfr_tan (x, x, MPFR_RNDN);
185 if (mpfr_cmp_si (x, -1))
186 {
187 printf ("tan(3*Pi/4) fails for prec=%u\n", prec2[i]);
188 exit (1);
189 }
190 }
191
192 mpfr_clear (x);
193
194 test_generic (MPFR_PREC_MIN, 100, 10);
195
196 data_check ("data/tan", mpfr_tan, "mpfr_tan");
197 bad_cases (mpfr_tan, mpfr_atan, "mpfr_tan", 256, -256, 255, 4, 128, 800, 40);
198
199 tests_end_mpfr ();
200 return 0;
201 }