1/* Test file for mpfr_factorial.
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
25#define TEST_FUNCTION mpfr_fac_ui
26
27static void
28special (void)
29{
30  mpfr_t x, y;
31  int inex;
32
33  mpfr_init (x);
34  mpfr_init (y);
35
36  mpfr_set_prec (x, 21);
37  mpfr_set_prec (y, 21);
38  mpfr_fac_ui (x, 119, MPFR_RNDZ);
39  mpfr_set_str_binary (y, "0.101111101110100110110E654");
40  if (mpfr_cmp (x, y))
41    {
42      printf ("Error in mpfr_fac_ui (119)\n");
43      exit (1);
44    }
45
46  mpfr_set_prec (y, 206);
47  inex = mpfr_fac_ui (y, 767, MPFR_RNDN);
48  mpfr_set_prec (x, 206);
49  mpfr_set_str_binary (x, "0.110111100001000001101010010001000111000100000100111000010011100011011111001100011110101000111101101100110001001100110100001001111110000101010000100100011100010011101110000001000010001100010000101001111E6250");
50  if (mpfr_cmp (x, y))
51    {
52      printf ("Error in mpfr_fac_ui (767)\n");
53      exit (1);
54    }
55  if (inex <= 0)
56    {
57      printf ("Wrong flag for mpfr_fac_ui (767)\n");
58      exit (1);
59    }
60
61  mpfr_set_prec (y, 202);
62  mpfr_fac_ui (y, 69, MPFR_RNDU);
63
64  mpfr_clear (x);
65  mpfr_clear (y);
66}
67
68static void
69test_int (void)
70{
71  unsigned long n0 = 1, n1 = 80, n;
72  mpz_t f;
73  mpfr_t x, y;
74  mpfr_prec_t prec_f, p;
75  int r;
76  int inex1, inex2;
77
78  mpz_init (f);
79  mpfr_init (x);
80  mpfr_init (y);
81
82  mpz_fac_ui (f, n0 - 1);
83  for (n = n0; n <= n1; n++)
84    {
85      mpz_mul_ui (f, f, n); /* f = n! */
86      prec_f = mpz_sizeinbase (f, 2) - mpz_scan1 (f, 0);
87      for (p = MPFR_PREC_MIN; p <= prec_f; p++)
88        {
89          mpfr_set_prec (x, p);
90          mpfr_set_prec (y, p);
91          RND_LOOP (r)
92            {
93              if ((mpfr_rnd_t) r == MPFR_RNDF)
94                continue;
95              inex1 = mpfr_fac_ui (x, n, (mpfr_rnd_t) r);
96              inex2 = mpfr_set_z (y, f, (mpfr_rnd_t) r);
97              if (mpfr_cmp (x, y))
98                {
99                  printf ("Error for n=%lu prec=%lu rnd=%s\n",
100                          n, (unsigned long) p, mpfr_print_rnd_mode ((mpfr_rnd_t) r));
101                  exit (1);
102                }
103              if ((inex1 < 0 && inex2 >= 0) || (inex1 == 0 && inex2 != 0)
104                  || (inex1 > 0 && inex2 <= 0))
105                {
106                  printf ("Wrong inexact flag for n=%lu prec=%lu rnd=%s\n",
107                          n, (unsigned long) p, mpfr_print_rnd_mode ((mpfr_rnd_t) r));
108                  printf ("Expected %d, got %d\n", inex2, inex1);
109                  exit (1);
110                }
111            }
112        }
113    }
114
115  mpz_clear (f);
116  mpfr_clear (x);
117  mpfr_clear (y);
118}
119
120static void
121overflowed_fac0 (void)
122{
123  mpfr_t x, y;
124  int inex, rnd, err = 0;
125  mpfr_exp_t old_emax;
126
127  old_emax = mpfr_get_emax ();
128
129  mpfr_init2 (x, 8);
130  mpfr_init2 (y, 8);
131
132  mpfr_set_ui (y, 1, MPFR_RNDN);
133  mpfr_nextbelow (y);
134  set_emax (0);  /* 1 is not representable. */
135  RND_LOOP (rnd)
136    {
137      mpfr_clear_flags ();
138      inex = mpfr_fac_ui (x, 0, (mpfr_rnd_t) rnd);
139      if (! mpfr_overflow_p ())
140        {
141          printf ("Error in overflowed_fac0 (rnd = %s):\n"
142                  "  The overflow flag is not set.\n",
143                  mpfr_print_rnd_mode ((mpfr_rnd_t) rnd));
144          err = 1;
145        }
146      if (rnd == MPFR_RNDZ || rnd == MPFR_RNDD)
147        {
148          if (inex >= 0)
149            {
150              printf ("Error in overflowed_fac0 (rnd = %s):\n"
151                      "  The inexact value must be negative.\n",
152                      mpfr_print_rnd_mode ((mpfr_rnd_t) rnd));
153              err = 1;
154            }
155          if (! mpfr_equal_p (x, y))
156            {
157              printf ("Error in overflowed_fac0 (rnd = %s):\n"
158                      "  Got        ",
159                      mpfr_print_rnd_mode ((mpfr_rnd_t) rnd));
160              mpfr_dump (x);
161              printf ("  instead of 0.11111111E0.\n");
162              err = 1;
163            }
164        }
165      else if (rnd != MPFR_RNDF)
166        {
167          if (inex <= 0)
168            {
169              printf ("Error in overflowed_fac0 (rnd = %s):\n"
170                      "  The inexact value must be positive.\n",
171                      mpfr_print_rnd_mode ((mpfr_rnd_t) rnd));
172              err = 1;
173            }
174          if (! (mpfr_inf_p (x) && MPFR_IS_POS (x)))
175            {
176              printf ("Error in overflowed_fac0 (rnd = %s):\n"
177                      "  Got        ",
178                      mpfr_print_rnd_mode ((mpfr_rnd_t) rnd));
179              mpfr_dump (x);
180              printf ("  instead of +Inf.\n");
181              err = 1;
182            }
183        }
184    }
185  set_emax (old_emax);
186
187  if (err)
188    exit (1);
189  mpfr_clear (x);
190  mpfr_clear (y);
191}
192
193int
194main (int argc, char *argv[])
195{
196  unsigned int err, k, zeros;
197  unsigned long n;
198  int rnd;
199  mpfr_t x, y, z, t;
200  int inexact;
201  unsigned long prec, yprec;
202
203  tests_start_mpfr ();
204
205  special ();
206
207  test_int ();
208
209  mpfr_init (x);
210  mpfr_init (y);
211  mpfr_init (z);
212  mpfr_init (t);
213
214  mpfr_fac_ui (y, 0, MPFR_RNDN);
215
216  if (mpfr_cmp_ui (y, 1))
217    {
218      printf ("mpfr_fac_ui(0) does not give 1\n");
219      exit (1);
220    }
221
222  for (prec = MPFR_PREC_MIN; prec <= 100; prec++)
223    {
224      mpfr_set_prec (x, prec);
225      mpfr_set_prec (z, prec);
226      mpfr_set_prec (t, prec);
227      yprec = prec + 10;
228      mpfr_set_prec (y, yprec);
229
230      for (n = 0; n < 50; n++)
231        RND_LOOP (rnd)
232          {
233            if ((mpfr_rnd_t) rnd == MPFR_RNDF)
234              continue;
235            inexact = mpfr_fac_ui (y, n, (mpfr_rnd_t) rnd);
236            err = (rnd == MPFR_RNDN) ? yprec + 1 : yprec;
237            if (mpfr_can_round (y, err, (mpfr_rnd_t) rnd, (mpfr_rnd_t) rnd, prec))
238              {
239                mpfr_set (t, y, (mpfr_rnd_t) rnd);
240                inexact = mpfr_fac_ui (z, n, (mpfr_rnd_t) rnd);
241                /* fact(n) ends with floor(n/2)+floor(n/4)+... zeros */
242                for (k=n/2, zeros=0; k; k >>= 1)
243                  zeros += k;
244                if (MPFR_EXP(y) <= (mpfr_exp_t) (prec + zeros))
245                  /* result should be exact */
246                  {
247                    if (inexact)
248                      {
249                        printf ("Wrong inexact flag: expected exact\n");
250                        printf ("n=%lu prec=%lu rnd=%s\n", n, prec,
251                                mpfr_print_rnd_mode ((mpfr_rnd_t) rnd));
252                        mpfr_dump (z);
253                        exit (1);
254                      }
255                  }
256                else /* result is inexact */
257                  {
258                    if (!inexact)
259                      {
260                        printf ("Wrong inexact flag: expected inexact\n");
261                        printf ("n=%lu prec=%lu rnd=%s\n", n, prec,
262                                mpfr_print_rnd_mode ((mpfr_rnd_t) rnd));
263                        mpfr_dump (z);
264                        exit (1);
265                      }
266                  }
267                if (mpfr_cmp (t, z))
268                  {
269                    printf ("results differ for x=");
270                    mpfr_out_str (stdout, 2, prec, x, MPFR_RNDN);
271                    printf (" prec=%lu rnd_mode=%s\n", prec,
272                            mpfr_print_rnd_mode ((mpfr_rnd_t) rnd));
273                    printf ("   got               ");
274                    mpfr_dump (z);
275                    printf ("   expected          ");
276                    mpfr_dump (t);
277                    printf ("   approximation was ");
278                    mpfr_dump (y);
279                    exit (1);
280                  }
281              }
282          }
283    }
284
285  mpfr_clear (x);
286  mpfr_clear (y);
287  mpfr_clear (z);
288  mpfr_clear (t);
289
290  overflowed_fac0 ();
291
292  tests_end_mpfr ();
293  return 0;
294}
295