2 * Copyright (c) 2008 David Schultz <das@FreeBSD.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * Tests for corner cases in the inverse trigonometric functions. Some
29 * accuracy tests are included as well, but these are very basic
30 * sanity checks, not intended to be comprehensive.
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
42 #include "test-utils.h"
44 #pragma STDC FENV_ACCESS ON
47 * Test that a function returns the correct value and sets the
48 * exception flags correctly. A tolerance specifying the maximum
49 * relative error allowed may be specified. For the 'testall'
50 * functions, the tolerance is specified in ulps.
52 * These are macros instead of functions so that assert provides more
53 * meaningful error messages.
55 #define test_tol(func, x, result, tol, excepts) do { \
56 volatile long double _in = (x), _out = (result); \
57 assert(feclearexcept(FE_ALL_EXCEPT) == 0); \
58 assert(fpequal_tol(func(_in), _out, (tol), CS_BOTH)); \
59 assert(((void)func, fetestexcept(ALL_STD_EXCEPT) == (excepts))); \
61 #define test(func, x, result, excepts) \
62 test_tol(func, (x), (result), 0, (excepts))
64 #define _testall_tol(prefix, x, result, tol, excepts) do { \
65 test_tol(prefix, (double)(x), (double)(result), \
66 (tol) * ldexp(1.0, 1 - DBL_MANT_DIG), (excepts)); \
67 test_tol(prefix##f, (float)(x), (float)(result), \
68 (tol) * ldexpf(1.0, 1 - FLT_MANT_DIG), (excepts)); \
72 #define testall_tol _testall_tol
74 #define testall_tol(prefix, x, result, tol, excepts) do { \
75 _testall_tol(prefix, x, result, tol, excepts); \
76 test_tol(prefix##l, (x), (result), \
77 (tol) * ldexpl(1.0, 1 - LDBL_MANT_DIG), (excepts)); \
81 #define testall(prefix, x, result, excepts) \
82 testall_tol(prefix, (x), (result), 0, (excepts))
84 #define test2_tol(func, y, x, result, tol, excepts) do { \
85 volatile long double _iny = (y), _inx = (x), _out = (result); \
86 assert(feclearexcept(FE_ALL_EXCEPT) == 0); \
87 assert(fpequal_tol(func(_iny, _inx), _out, (tol), CS_BOTH)); \
88 assert(((void)func, fetestexcept(ALL_STD_EXCEPT) == (excepts))); \
90 #define test2(func, y, x, result, excepts) \
91 test2_tol(func, (y), (x), (result), 0, (excepts))
93 #define _testall2_tol(prefix, y, x, result, tol, excepts) do { \
94 test2_tol(prefix, (double)(y), (double)(x), (double)(result), \
95 (tol) * ldexp(1.0, 1 - DBL_MANT_DIG), (excepts)); \
96 test2_tol(prefix##f, (float)(y), (float)(x), (float)(result), \
97 (tol) * ldexpf(1.0, 1 - FLT_MANT_DIG), (excepts)); \
101 #define testall2_tol _testall2_tol
103 #define testall2_tol(prefix, y, x, result, tol, excepts) do { \
104 _testall2_tol(prefix, y, x, result, tol, excepts); \
105 test2_tol(prefix##l, (y), (x), (result), \
106 (tol) * ldexpl(1.0, 1 - LDBL_MANT_DIG), (excepts)); \
110 #define testall2(prefix, y, x, result, excepts) \
111 testall2_tol(prefix, (y), (x), (result), 0, (excepts))
114 pi = 3.14159265358979323846264338327950280e+00L,
115 pio3 = 1.04719755119659774615421446109316766e+00L,
116 c3pi = 9.42477796076937971538793014983850839e+00L,
117 c5pi = 1.57079632679489661923132169163975140e+01L,
118 c7pi = 2.19911485751285526692385036829565196e+01L,
119 c5pio3 = 5.23598775598298873077107230546583851e+00L,
120 sqrt2m1 = 4.14213562373095048801688724209698081e-01L;
124 * Test special case inputs in asin(), acos() and atan(): signed
125 * zeroes, infinities, and NaNs.
131 testall(asin, 0.0, 0.0, 0);
132 testall(acos, 0.0, pi / 2, FE_INEXACT);
133 testall(atan, 0.0, 0.0, 0);
134 testall(asin, -0.0, -0.0, 0);
135 testall(acos, -0.0, pi / 2, FE_INEXACT);
136 testall(atan, -0.0, -0.0, 0);
138 testall(asin, INFINITY, NAN, FE_INVALID);
139 testall(acos, INFINITY, NAN, FE_INVALID);
140 testall(atan, INFINITY, pi / 2, FE_INEXACT);
141 testall(asin, -INFINITY, NAN, FE_INVALID);
142 testall(acos, -INFINITY, NAN, FE_INVALID);
143 testall(atan, -INFINITY, -pi / 2, FE_INEXACT);
145 testall(asin, NAN, NAN, 0);
146 testall(acos, NAN, NAN, 0);
147 testall(atan, NAN, NAN, 0);
151 * Test special case inputs in atan2(), where the exact value of y/x is
152 * zero or non-finite.
155 test_special_atan2(void)
160 testall2(atan2, 0.0, -0.0, pi, FE_INEXACT);
161 testall2(atan2, -0.0, -0.0, -pi, FE_INEXACT);
162 testall2(atan2, 0.0, 0.0, 0.0, 0);
163 testall2(atan2, -0.0, 0.0, -0.0, 0);
165 testall2(atan2, INFINITY, -INFINITY, c3pi / 4, FE_INEXACT);
166 testall2(atan2, -INFINITY, -INFINITY, -c3pi / 4, FE_INEXACT);
167 testall2(atan2, INFINITY, INFINITY, pi / 4, FE_INEXACT);
168 testall2(atan2, -INFINITY, INFINITY, -pi / 4, FE_INEXACT);
170 /* Tests with one input in the range (0, Inf]. */
172 for (e = FLT_MIN_EXP - FLT_MANT_DIG; e <= FLT_MAX_EXP; e++) {
173 test2(atan2f, 0.0, ldexpf(z, e), 0.0, 0);
174 test2(atan2f, -0.0, ldexpf(z, e), -0.0, 0);
175 test2(atan2f, 0.0, ldexpf(-z, e), (float)pi, FE_INEXACT);
176 test2(atan2f, -0.0, ldexpf(-z, e), (float)-pi, FE_INEXACT);
177 test2(atan2f, ldexpf(z, e), 0.0, (float)pi / 2, FE_INEXACT);
178 test2(atan2f, ldexpf(z, e), -0.0, (float)pi / 2, FE_INEXACT);
179 test2(atan2f, ldexpf(-z, e), 0.0, (float)-pi / 2, FE_INEXACT);
180 test2(atan2f, ldexpf(-z, e), -0.0, (float)-pi / 2, FE_INEXACT);
182 for (e = DBL_MIN_EXP - DBL_MANT_DIG; e <= DBL_MAX_EXP; e++) {
183 test2(atan2, 0.0, ldexp(z, e), 0.0, 0);
184 test2(atan2, -0.0, ldexp(z, e), -0.0, 0);
185 test2(atan2, 0.0, ldexp(-z, e), (double)pi, FE_INEXACT);
186 test2(atan2, -0.0, ldexp(-z, e), (double)-pi, FE_INEXACT);
187 test2(atan2, ldexp(z, e), 0.0, (double)pi / 2, FE_INEXACT);
188 test2(atan2, ldexp(z, e), -0.0, (double)pi / 2, FE_INEXACT);
189 test2(atan2, ldexp(-z, e), 0.0, (double)-pi / 2, FE_INEXACT);
190 test2(atan2, ldexp(-z, e), -0.0, (double)-pi / 2, FE_INEXACT);
192 for (e = LDBL_MIN_EXP - LDBL_MANT_DIG; e <= LDBL_MAX_EXP; e++) {
193 test2(atan2l, 0.0, ldexpl(z, e), 0.0, 0);
194 test2(atan2l, -0.0, ldexpl(z, e), -0.0, 0);
195 test2(atan2l, 0.0, ldexpl(-z, e), pi, FE_INEXACT);
196 test2(atan2l, -0.0, ldexpl(-z, e), -pi, FE_INEXACT);
197 test2(atan2l, ldexpl(z, e), 0.0, pi / 2, FE_INEXACT);
198 test2(atan2l, ldexpl(z, e), -0.0, pi / 2, FE_INEXACT);
199 test2(atan2l, ldexpl(-z, e), 0.0, -pi / 2, FE_INEXACT);
200 test2(atan2l, ldexpl(-z, e), -0.0, -pi / 2, FE_INEXACT);
203 /* Tests with one input in the range (0, Inf). */
204 for (e = FLT_MIN_EXP - FLT_MANT_DIG; e <= FLT_MAX_EXP - 1; e++) {
205 test2(atan2f, ldexpf(z, e), INFINITY, 0.0, 0);
206 test2(atan2f, ldexpf(-z,e), INFINITY, -0.0, 0);
207 test2(atan2f, ldexpf(z, e), -INFINITY, (float)pi, FE_INEXACT);
208 test2(atan2f, ldexpf(-z,e), -INFINITY, (float)-pi, FE_INEXACT);
209 test2(atan2f, INFINITY, ldexpf(z,e), (float)pi/2, FE_INEXACT);
210 test2(atan2f, INFINITY, ldexpf(-z,e), (float)pi/2, FE_INEXACT);
211 test2(atan2f, -INFINITY, ldexpf(z,e), (float)-pi/2,FE_INEXACT);
212 test2(atan2f, -INFINITY, ldexpf(-z,e),(float)-pi/2,FE_INEXACT);
214 for (e = DBL_MIN_EXP - DBL_MANT_DIG; e <= DBL_MAX_EXP - 1; e++) {
215 test2(atan2, ldexp(z, e), INFINITY, 0.0, 0);
216 test2(atan2, ldexp(-z,e), INFINITY, -0.0, 0);
217 test2(atan2, ldexp(z, e), -INFINITY, (double)pi, FE_INEXACT);
218 test2(atan2, ldexp(-z,e), -INFINITY, (double)-pi, FE_INEXACT);
219 test2(atan2, INFINITY, ldexp(z,e), (double)pi/2, FE_INEXACT);
220 test2(atan2, INFINITY, ldexp(-z,e), (double)pi/2, FE_INEXACT);
221 test2(atan2, -INFINITY, ldexp(z,e), (double)-pi/2,FE_INEXACT);
222 test2(atan2, -INFINITY, ldexp(-z,e),(double)-pi/2,FE_INEXACT);
224 for (e = LDBL_MIN_EXP - LDBL_MANT_DIG; e <= LDBL_MAX_EXP - 1; e++) {
225 test2(atan2l, ldexpl(z, e), INFINITY, 0.0, 0);
226 test2(atan2l, ldexpl(-z,e), INFINITY, -0.0, 0);
227 test2(atan2l, ldexpl(z, e), -INFINITY, pi, FE_INEXACT);
228 test2(atan2l, ldexpl(-z,e), -INFINITY, -pi, FE_INEXACT);
229 test2(atan2l, INFINITY, ldexpl(z, e), pi / 2, FE_INEXACT);
230 test2(atan2l, INFINITY, ldexpl(-z, e), pi / 2, FE_INEXACT);
231 test2(atan2l, -INFINITY, ldexpl(z, e), -pi / 2, FE_INEXACT);
232 test2(atan2l, -INFINITY, ldexpl(-z, e), -pi / 2, FE_INEXACT);
237 * Test various inputs to asin(), acos() and atan() and verify that the
238 * results are accurate to within 1 ulp.
244 /* We expect correctly rounded results for these basic cases. */
245 testall(asin, 1.0, pi / 2, FE_INEXACT);
246 testall(acos, 1.0, 0, 0);
247 testall(atan, 1.0, pi / 4, FE_INEXACT);
248 testall(asin, -1.0, -pi / 2, FE_INEXACT);
249 testall(acos, -1.0, pi, FE_INEXACT);
250 testall(atan, -1.0, -pi / 4, FE_INEXACT);
253 * Here we expect answers to be within 1 ulp, although inexactness
254 * in the input, combined with double rounding, could cause larger
258 testall_tol(asin, sqrtl(2) / 2, pi / 4, 1, FE_INEXACT);
259 testall_tol(acos, sqrtl(2) / 2, pi / 4, 1, FE_INEXACT);
260 testall_tol(asin, -sqrtl(2) / 2, -pi / 4, 1, FE_INEXACT);
261 testall_tol(acos, -sqrtl(2) / 2, c3pi / 4, 1, FE_INEXACT);
263 testall_tol(asin, sqrtl(3) / 2, pio3, 1, FE_INEXACT);
264 testall_tol(acos, sqrtl(3) / 2, pio3 / 2, 1, FE_INEXACT);
265 testall_tol(atan, sqrtl(3), pio3, 1, FE_INEXACT);
266 testall_tol(asin, -sqrtl(3) / 2, -pio3, 1, FE_INEXACT);
267 testall_tol(acos, -sqrtl(3) / 2, c5pio3 / 2, 1, FE_INEXACT);
268 testall_tol(atan, -sqrtl(3), -pio3, 1, FE_INEXACT);
270 testall_tol(atan, sqrt2m1, pi / 8, 1, FE_INEXACT);
271 testall_tol(atan, -sqrt2m1, -pi / 8, 1, FE_INEXACT);
275 * Test inputs to atan2() where x is a power of 2. These are easy cases
276 * because y/x is exact.
282 testall2(atan2, 1.0, 1.0, pi / 4, FE_INEXACT);
283 testall2(atan2, 1.0, -1.0, c3pi / 4, FE_INEXACT);
284 testall2(atan2, -1.0, 1.0, -pi / 4, FE_INEXACT);
285 testall2(atan2, -1.0, -1.0, -c3pi / 4, FE_INEXACT);
287 testall2_tol(atan2, sqrt2m1 * 2, 2.0, pi / 8, 1, FE_INEXACT);
288 testall2_tol(atan2, sqrt2m1 * 2, -2.0, c7pi / 8, 1, FE_INEXACT);
289 testall2_tol(atan2, -sqrt2m1 * 2, 2.0, -pi / 8, 1, FE_INEXACT);
290 testall2_tol(atan2, -sqrt2m1 * 2, -2.0, -c7pi / 8, 1, FE_INEXACT);
292 testall2_tol(atan2, sqrtl(3) * 0.5, 0.5, pio3, 1, FE_INEXACT);
293 testall2_tol(atan2, sqrtl(3) * 0.5, -0.5, pio3 * 2, 1, FE_INEXACT);
294 testall2_tol(atan2, -sqrtl(3) * 0.5, 0.5, -pio3, 1, FE_INEXACT);
295 testall2_tol(atan2, -sqrtl(3) * 0.5, -0.5, -pio3 * 2, 1, FE_INEXACT);
299 * Test inputs very close to 0.
304 float tiny = 0x1.23456p-120f;
306 testall(asin, tiny, tiny, FE_INEXACT);
307 testall(acos, tiny, pi / 2, FE_INEXACT);
308 testall(atan, tiny, tiny, FE_INEXACT);
310 testall(asin, -tiny, -tiny, FE_INEXACT);
311 testall(acos, -tiny, pi / 2, FE_INEXACT);
312 testall(atan, -tiny, -tiny, FE_INEXACT);
314 /* Test inputs to atan2() that would cause y/x to underflow. */
315 test2(atan2f, 0x1.0p-100, 0x1.0p100, 0.0, FE_INEXACT | FE_UNDERFLOW);
316 test2(atan2, 0x1.0p-1000, 0x1.0p1000, 0.0, FE_INEXACT | FE_UNDERFLOW);
317 test2(atan2l, ldexpl(1.0, 100 - LDBL_MAX_EXP),
318 ldexpl(1.0, LDBL_MAX_EXP - 100), 0.0, FE_INEXACT | FE_UNDERFLOW);
319 test2(atan2f, -0x1.0p-100, 0x1.0p100, -0.0, FE_INEXACT | FE_UNDERFLOW);
320 test2(atan2, -0x1.0p-1000, 0x1.0p1000, -0.0, FE_INEXACT | FE_UNDERFLOW);
321 test2(atan2l, -ldexpl(1.0, 100 - LDBL_MAX_EXP),
322 ldexpl(1.0, LDBL_MAX_EXP - 100), -0.0, FE_INEXACT | FE_UNDERFLOW);
323 test2(atan2f, 0x1.0p-100, -0x1.0p100, (float)pi, FE_INEXACT);
324 test2(atan2, 0x1.0p-1000, -0x1.0p1000, (double)pi, FE_INEXACT);
325 test2(atan2l, ldexpl(1.0, 100 - LDBL_MAX_EXP),
326 -ldexpl(1.0, LDBL_MAX_EXP - 100), pi, FE_INEXACT);
327 test2(atan2f, -0x1.0p-100, -0x1.0p100, (float)-pi, FE_INEXACT);
328 test2(atan2, -0x1.0p-1000, -0x1.0p1000, (double)-pi, FE_INEXACT);
329 test2(atan2l, -ldexpl(1.0, 100 - LDBL_MAX_EXP),
330 -ldexpl(1.0, LDBL_MAX_EXP - 100), -pi, FE_INEXACT);
334 * Test very large inputs to atan().
339 float huge = 0x1.23456p120;
341 testall(atan, huge, pi / 2, FE_INEXACT);
342 testall(atan, -huge, -pi / 2, FE_INEXACT);
344 /* Test inputs to atan2() that would cause y/x to overflow. */
345 test2(atan2f, 0x1.0p100, 0x1.0p-100, (float)pi / 2, FE_INEXACT);
346 test2(atan2, 0x1.0p1000, 0x1.0p-1000, (double)pi / 2, FE_INEXACT);
347 test2(atan2l, ldexpl(1.0, LDBL_MAX_EXP - 100),
348 ldexpl(1.0, 100 - LDBL_MAX_EXP), pi / 2, FE_INEXACT);
349 test2(atan2f, -0x1.0p100, 0x1.0p-100, (float)-pi / 2, FE_INEXACT);
350 test2(atan2, -0x1.0p1000, 0x1.0p-1000, (double)-pi / 2, FE_INEXACT);
351 test2(atan2l, -ldexpl(1.0, LDBL_MAX_EXP - 100),
352 ldexpl(1.0, 100 - LDBL_MAX_EXP), -pi / 2, FE_INEXACT);
354 test2(atan2f, 0x1.0p100, -0x1.0p-100, (float)pi / 2, FE_INEXACT);
355 test2(atan2, 0x1.0p1000, -0x1.0p-1000, (double)pi / 2, FE_INEXACT);
356 test2(atan2l, ldexpl(1.0, LDBL_MAX_EXP - 100),
357 -ldexpl(1.0, 100 - LDBL_MAX_EXP), pi / 2, FE_INEXACT);
358 test2(atan2f, -0x1.0p100, -0x1.0p-100, (float)-pi / 2, FE_INEXACT);
359 test2(atan2, -0x1.0p1000, -0x1.0p-1000, (double)-pi / 2, FE_INEXACT);
360 test2(atan2l, -ldexpl(1.0, LDBL_MAX_EXP - 100),
361 -ldexpl(1.0, 100 - LDBL_MAX_EXP), -pi / 2, FE_INEXACT);
365 * Test that sin(asin(x)) == x, and similarly for acos() and atan().
366 * You need to have a working sinl(), cosl(), and tanl() for these
373 return (sinl(asinf(x)));
380 return (sinl(asin(x)));
384 sinasinl(long double x)
387 return (sinl(asinl(x)));
394 return (cosl(acosf(x)));
401 return (cosl(acos(x)));
405 cosacosl(long double x)
408 return (cosl(acosl(x)));
415 return (tanl(atanf(x)));
422 return (tanl(atan(x)));
426 tanatanl(long double x)
429 return (tanl(atanl(x)));
437 for (i = -1; i <= 1; i += 0x1.0p-12f) {
438 testall_tol(sinasin, i, i, 2, i == 0 ? 0 : FE_INEXACT);
439 /* The relative error for cosacos is very large near x=0. */
440 if (fabsf(i) > 0x1.0p-4f)
441 testall_tol(cosacos, i, i, 16, i == 1 ? 0 : FE_INEXACT);
442 testall_tol(tanatan, i, i, 2, i == 0 ? 0 : FE_INEXACT);
447 main(int argc, char *argv[])
450 #if defined(__i386__)
451 printf("1..0 # SKIP fails all assertions on i386\n");
458 printf("ok 1 - special\n");
460 test_special_atan2();
461 printf("ok 2 - atan2 special\n");
464 printf("ok 3 - accuracy\n");
467 printf("ok 4 - atan2 p2x\n");
470 printf("ok 5 - tiny inputs\n");
473 printf("ok 6 - atan huge inputs\n");
476 printf("ok 7 - inverse\n");