1/* Test file for mpfr_ui_pow and mpfr_ui_pow_ui.
2
3Copyright 2001-2023 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
25static void
26test1 (void)
27{
28  mpfr_t x, y, z, a;
29  int res1, res2;
30
31  mpfr_init2 (x, 32);
32  mpfr_init2 (y, 65);
33  mpfr_init2 (z, 17);
34  mpfr_init2 (a, 17);
35
36  mpfr_set_str_binary (x, "-0.101110001001011011011e-9");
37  mpfr_ui_pow (y, 7, x, MPFR_RNDN);
38
39  mpfr_set_prec (x, 40);
40  mpfr_set_str_binary (x, "-0.1100101100101111011001010010110011110110E-1");
41  mpfr_set_prec (y, 74);
42  mpfr_ui_pow (y, 8, x, MPFR_RNDN);
43  mpfr_set_prec (x, 74);
44  mpfr_set_str_binary (x, "0.11100000010100111101000011111011011010011000011000101011010011010101000011E-1");
45  if (mpfr_cmp (x, y))
46    {
47      printf ("Error for input of 40 bits, output of 74 bits\n");
48      exit (1);
49    }
50
51  /* Check for ui_pow_ui */
52  mpfr_ui_pow_ui (x, 0, 1, MPFR_RNDN);
53  MPFR_ASSERTN(mpfr_cmp_ui (x, 0) == 0 && MPFR_IS_POS (x));
54  mpfr_ui_pow_ui (x, 0, 4, MPFR_RNDN);
55  MPFR_ASSERTN(mpfr_cmp_ui (x, 0) == 0 && MPFR_IS_POS (x));
56  res1 = mpfr_ui_pow_ui (z, 17, 42, MPFR_RNDD);
57  mpfr_set_ui (x, 17, MPFR_RNDN);
58  mpfr_set_ui (y, 42, MPFR_RNDN);
59  res2 = mpfr_pow (a, x, y, MPFR_RNDD);
60  if (mpfr_cmp (z, a) || res1 != res2)
61    {
62      printf ("Error for ui_pow_ui for 17^42\n"
63              "Inexact1 = %d Inexact2 = %d\n", res1, res2);
64      mpfr_dump (z);
65      mpfr_dump (a);
66      exit (1);
67    }
68  mpfr_set_prec (x, 2);
69  mpfr_ui_pow_ui (x, 65537, 65535, MPFR_RNDN);
70  if (mpfr_cmp_str (x, "0.11E1048562", 2, MPFR_RNDN) != 0)
71    {
72      printf ("Error for ui_pow_ui for 65537 ^65535 with 2 bits of precision\n");
73      mpfr_dump (x);
74      exit (1);
75    }
76  mpfr_clear (x);
77  mpfr_clear (y);
78  mpfr_clear (z);
79  mpfr_clear (a);
80}
81
82static void
83check1 (mpfr_ptr x, mpfr_prec_t prec, unsigned long nt, mpfr_rnd_t rnd)
84{
85  mpfr_t y, z, t;
86  int inexact, compare, compare2;
87  mpfr_prec_t yprec;
88  mpfr_exp_t err;
89
90  yprec = prec + 10;
91
92  mpfr_init (y);
93  mpfr_init (z);
94  mpfr_init (t);
95  mpfr_set_prec (y, yprec);
96  mpfr_set_prec (z, prec);
97  mpfr_set_prec (t, prec);
98
99  compare = mpfr_ui_pow (y, nt, x, rnd);
100  err = (rnd == MPFR_RNDN) ? yprec + 1 : yprec;
101  if (mpfr_can_round (y, err, rnd, rnd, prec))
102    {
103      mpfr_set (t, y, rnd);
104      inexact = mpfr_ui_pow (z, nt, x, rnd);
105      if (mpfr_cmp (t, z))
106        {
107          printf ("results differ for x=");
108          mpfr_out_str (stdout, 2, prec, x, MPFR_RNDN);
109          printf (" n=%lu", nt);
110          printf (" prec=%u rnd_mode=%s\n", (unsigned) prec,
111                  mpfr_print_rnd_mode (rnd));
112          printf ("got      ");
113          mpfr_dump (z);
114          printf ("expected ");
115          mpfr_dump (t);
116          printf ("approx   ");
117          mpfr_dump (y);
118          exit (1);
119        }
120      compare2 = mpfr_cmp (t, y);
121      /* if rounding to nearest, cannot know the sign of t - f(x)
122         because of composed rounding: y = o(f(x)) and t = o(y) */
123      if ((rnd != MPFR_RNDN) && (compare * compare2 >= 0))
124        compare = compare + compare2;
125      else
126        compare = inexact; /* cannot determine sign(t-f(x)) */
127      if (((inexact == 0) && (compare != 0)) ||
128          ((inexact > 0) && (compare <= 0)) ||
129          ((inexact < 0) && (compare >= 0)))
130        {
131          printf ("Wrong inexact flag for rnd=%s: expected %d, got %d\n",
132                  mpfr_print_rnd_mode (rnd), compare, inexact);
133          printf ("x="); mpfr_dump (x);
134          printf ("y="); mpfr_dump (y);
135          printf ("t="); mpfr_dump (t);
136          exit (1);
137        }
138    }
139
140  mpfr_clear (y);
141  mpfr_clear (z);
142  mpfr_clear (t);
143}
144
145static void
146huge (void)
147{
148  mpfr_exp_t old_emin, old_emax;
149  mpfr_t x;
150
151  old_emin = mpfr_get_emin ();
152  old_emax = mpfr_get_emax ();
153
154  set_emin (MPFR_EMIN_MIN);
155  set_emax (MPFR_EMAX_MAX);
156
157  mpfr_init2 (x, 8);
158
159  /* The purpose of this test is more to check that mpfr_ui_pow_ui
160     terminates (without taking much memory) rather than checking
161     the value of x. On 2023-02-13, the +Inf case was not handled
162     in the Ziv iteration, yielding an infinite loop, affecting
163     mpfr_log10 in particular. See
164       commit 90de094f0d9c309daca707aa227470d810866616
165  */
166  mpfr_ui_pow_ui (x, 5, ULONG_MAX, MPFR_RNDN);
167  if (MPFR_EMAX_MAX <= ULONG_MAX)  /* true with default _MPFR_EXP_FORMAT */
168    MPFR_ASSERTN (MPFR_IS_INF (x));
169
170  mpfr_clear (x);
171
172  set_emin (old_emin);
173  set_emax (old_emax);
174}
175
176static void
177test2 (void)
178{
179  mpfr_t x, y, z, t;
180  mpfr_prec_t prec;
181  mpfr_rnd_t rnd;
182  unsigned int n;
183  mpfr_prec_t p0 = 2, p1 = 100;
184  unsigned int N = 20;
185
186  mpfr_init2 (x, 2);
187  mpfr_init2 (y, 2);
188  mpfr_init2 (z, 38);
189  mpfr_init2 (t, 6);
190
191  /* check exact power */
192  mpfr_set_str_binary (t, "0.110000E5");
193  mpfr_ui_pow (z, 3, t, MPFR_RNDN);
194
195  mpfr_set_str (x, "-0.5", 10, MPFR_RNDZ);
196  mpfr_ui_pow (y, 4, x, MPFR_RNDD);
197  if (mpfr_cmp_ui_2exp (y, 1, -1))
198    {
199      printf ("Error for 4^(-0.5), prec=2, MPFR_RNDD\n");
200      printf ("expected 0.5, got ");
201      mpfr_out_str (stdout, 2, 0, y, MPFR_RNDN);
202      printf ("\n");
203      exit (1);
204    }
205
206  /* problem found by Kevin on spe175.testdrive.compaq.com
207     (03 Sep 2003), ia64 under HP-UX */
208  mpfr_set_str (x, "0.5", 10, MPFR_RNDN);
209  mpfr_ui_pow (y, 398441521, x, MPFR_RNDN);
210  if (mpfr_cmp_ui_2exp (y, 1, 14))
211    {
212      printf ("Error for 398441521^(0.5), prec=2, MPFR_RNDN\n");
213      printf ("expected 1.0e14, got ");
214      mpfr_out_str (stdout, 2, 0, y, MPFR_RNDN);
215      printf ("\n");
216      exit (1);
217    }
218
219  mpfr_set_str (x, "0.5", 10, MPFR_RNDN);
220  check1 (x, 2, 398441521, MPFR_RNDN);  /* 398441521 = 19961^2 */
221
222  /* generic test */
223  for (prec = p0; prec <= p1; prec++)
224    {
225      mpfr_set_prec (x, prec);
226      for (n = 0; n < N; n++)
227        {
228          int nt;
229          nt = randlimb () & INT_MAX;
230          mpfr_urandomb (x, RANDS);
231          rnd = RND_RAND_NO_RNDF ();
232          check1 (x, prec, nt, rnd);
233        }
234    }
235
236  mpfr_clears (x, y, z, t, (mpfr_ptr) 0);
237}
238
239/* reverse the arguments n and x for tgeneric_ui.c */
240static int
241ui_pow_rev (mpfr_ptr y, mpfr_srcptr x, unsigned long n, mpfr_rnd_t rnd)
242{
243  return mpfr_ui_pow (y, n, x, rnd);
244}
245
246#define TEST_FUNCTION ui_pow_rev
247#define INTEGER_TYPE  unsigned long
248#define RAND_FUNCTION(x) mpfr_random2(x, MPFR_LIMB_SIZE (x), 1, RANDS)
249#define INT_RAND_FUNCTION() \
250  (randlimb () % 16 == 0 ? randulong () : (unsigned long) (randlimb () % 32))
251#include "tgeneric_ui.c"
252
253int
254main (int argc, char *argv[])
255{
256  mpfr_t x, y;
257  unsigned long int n;
258
259  tests_start_mpfr ();
260
261  mpfr_init (x);
262  mpfr_init (y);
263
264  do n = randlimb (); while (n <= 1);
265
266  MPFR_SET_INF (x);
267  mpfr_ui_pow (y, n, x, MPFR_RNDN);
268  if (! MPFR_IS_INF (y))
269    {
270      printf ("evaluation of function at INF does not return INF\n");
271      exit (1);
272    }
273
274  MPFR_CHANGE_SIGN (x);
275  mpfr_ui_pow (y, n, x, MPFR_RNDN);
276  if (! MPFR_IS_ZERO (y))
277    {
278      printf ("evaluation of function in -INF does not return 0\n");
279      exit (1);
280    }
281
282  MPFR_SET_NAN (x);
283  mpfr_ui_pow (y, n, x, MPFR_RNDN);
284  if (! MPFR_IS_NAN (y))
285    {
286      printf ("evaluation of function in NAN does not return NAN\n");
287      exit (1);
288    }
289
290  mpfr_clear (x);
291  mpfr_clear (y);
292
293  test1 ();
294  test2 ();
295  huge ();
296
297  test_generic_ui (MPFR_PREC_MIN, 100, 100);
298
299  tests_end_mpfr ();
300  return 0;
301}
302