1/* Test file for mpfr_div_ui.
2
3Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
4Contributed by the Arenaire and Cacao 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
20http://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 <stdio.h>
24#include <stdlib.h>
25#include <float.h>
26
27#include "mpfr-test.h"
28
29static void
30check (const char *ds, unsigned long u, mpfr_rnd_t rnd, const char *es)
31{
32  mpfr_t x, y;
33
34  mpfr_init2 (x, 53);
35  mpfr_init2 (y, 53);
36  mpfr_set_str1 (x, ds);
37  mpfr_div_ui (y, x, u, rnd);
38  if (mpfr_cmp_str1 (y, es))
39    {
40      printf ("mpfr_div_ui failed for x=%s, u=%lu, rnd=%s\n", ds, u,
41              mpfr_print_rnd_mode (rnd));
42      printf ("expected result is %s, got", es);
43      mpfr_out_str(stdout, 10, 0, y, MPFR_RNDN);
44      exit (1);
45    }
46  mpfr_clear (x);
47  mpfr_clear (y);
48}
49
50static void
51special (void)
52{
53  mpfr_t x, y;
54  unsigned xprec, yprec;
55
56  mpfr_init (x);
57  mpfr_init (y);
58
59  mpfr_set_prec (x, 32);
60  mpfr_set_prec (y, 32);
61  mpfr_set_ui (x, 1, MPFR_RNDN);
62  mpfr_div_ui (y, x, 3, MPFR_RNDN);
63
64  mpfr_set_prec (x, 100);
65  mpfr_set_prec (y, 100);
66  mpfr_urandomb (x, RANDS);
67  mpfr_div_ui (y, x, 123456, MPFR_RNDN);
68  mpfr_set_ui (x, 0, MPFR_RNDN);
69  mpfr_div_ui (y, x, 123456789, MPFR_RNDN);
70  if (mpfr_cmp_ui (y, 0))
71    {
72      printf ("mpfr_div_ui gives non-zero for 0/ui\n");
73      exit (1);
74    }
75
76  /* bug found by Norbert Mueller, 21 Aug 2001 */
77  mpfr_set_prec (x, 110);
78  mpfr_set_prec (y, 60);
79  mpfr_set_str_binary (x, "0.110101110011111110011111001110011001110111000000111110001000111011000011E-44");
80  mpfr_div_ui (y, x, 17, MPFR_RNDN);
81  mpfr_set_str_binary (x, "0.11001010100101100011101110000001100001010110101001010011011E-48");
82  if (mpfr_cmp (x, y))
83    {
84      printf ("Error in x/17 for x=1/16!\n");
85      printf ("Expected ");
86      mpfr_out_str (stdout, 2, 0, x, MPFR_RNDN);
87      printf ("\nGot      ");
88      mpfr_out_str (stdout, 2, 0, y, MPFR_RNDN);
89      printf ("\n");
90      exit (1);
91    }
92
93  /* corner case */
94  mpfr_set_prec (x, 2 * mp_bits_per_limb);
95  mpfr_set_prec (y, 2);
96  mpfr_set_ui (x, 4, MPFR_RNDN);
97  mpfr_nextabove (x);
98  mpfr_div_ui (y, x, 2, MPFR_RNDN); /* exactly in the middle */
99  MPFR_ASSERTN(mpfr_cmp_ui (y, 2) == 0);
100
101  mpfr_set_prec (x, 3 * mp_bits_per_limb);
102  mpfr_set_prec (y, 2);
103  mpfr_set_ui (x, 2, MPFR_RNDN);
104  mpfr_nextabove (x);
105  mpfr_div_ui (y, x, 2, MPFR_RNDN);
106  MPFR_ASSERTN(mpfr_cmp_ui (y, 1) == 0);
107
108  mpfr_set_prec (x, 3 * mp_bits_per_limb);
109  mpfr_set_prec (y, 2);
110  mpfr_set_si (x, -4, MPFR_RNDN);
111  mpfr_nextbelow (x);
112  mpfr_div_ui (y, x, 2, MPFR_RNDD);
113  MPFR_ASSERTN(mpfr_cmp_si (y, -3) == 0);
114
115  for (xprec = 53; xprec <= 128; xprec++)
116    {
117      mpfr_set_prec (x, xprec);
118      mpfr_set_str_binary (x, "0.1100100100001111110011111000000011011100001100110111E2");
119      for (yprec = 53; yprec <= 128; yprec++)
120        {
121          mpfr_set_prec (y, yprec);
122          mpfr_div_ui (y, x, 1, MPFR_RNDN);
123          if (mpfr_cmp(x,y))
124            {
125              printf ("division by 1.0 fails for xprec=%u, yprec=%u\n", xprec, yprec);
126              printf ("expected "); mpfr_print_binary (x); puts ("");
127              printf ("got      "); mpfr_print_binary (y); puts ("");
128              exit (1);
129            }
130        }
131    }
132
133  /* Bug reported by Mark Dickinson, 6 Nov 2007 */
134  mpfr_set_si (x, 0, MPFR_RNDN);
135  mpfr_set_si (y, -1, MPFR_RNDN);
136  mpfr_div_ui (y, x, 4, MPFR_RNDN);
137  MPFR_ASSERTN(MPFR_IS_ZERO(y) && MPFR_IS_POS(y));
138
139  mpfr_clear (x);
140  mpfr_clear (y);
141}
142
143static void
144check_inexact (void)
145{
146  mpfr_t x, y, z;
147  mpfr_prec_t px, py;
148  int inexact, cmp;
149  unsigned long int u;
150  int rnd;
151
152  mpfr_init (x);
153  mpfr_init (y);
154  mpfr_init (z);
155
156  for (px=2; px<300; px++)
157    {
158      mpfr_set_prec (x, px);
159      mpfr_urandomb (x, RANDS);
160      do
161        {
162          u = randlimb ();
163        }
164      while (u == 0);
165      for (py=2; py<300; py++)
166        {
167          mpfr_set_prec (y, py);
168          mpfr_set_prec (z, py + mp_bits_per_limb);
169          for (rnd = 0; rnd < MPFR_RND_MAX; rnd++)
170            {
171              inexact = mpfr_div_ui (y, x, u, (mpfr_rnd_t) rnd);
172              if (mpfr_mul_ui (z, y, u, (mpfr_rnd_t) rnd))
173                {
174                  printf ("z <- y * u should be exact for u=%lu\n", u);
175                  printf ("y="); mpfr_print_binary (y); puts ("");
176                  printf ("z="); mpfr_print_binary (z); puts ("");
177                  exit (1);
178                }
179              cmp = mpfr_cmp (z, x);
180              if (((inexact == 0) && (cmp != 0)) ||
181                  ((inexact > 0) && (cmp <= 0)) ||
182                  ((inexact < 0) && (cmp >= 0)))
183                {
184                  printf ("Wrong inexact flag for u=%lu, rnd=%s\n", u,
185                          mpfr_print_rnd_mode ((mpfr_rnd_t) rnd));
186                  printf ("x="); mpfr_print_binary (x); puts ("");
187                  printf ("y="); mpfr_print_binary (y); puts ("");
188                  exit (1);
189                }
190            }
191        }
192    }
193
194  mpfr_clear (x);
195  mpfr_clear (y);
196  mpfr_clear (z);
197}
198
199#define TEST_FUNCTION mpfr_div_ui
200#define INTEGER_TYPE  unsigned long
201#define RAND_FUNCTION(x) mpfr_random2(x, MPFR_LIMB_SIZE (x), 1, RANDS)
202#include "tgeneric_ui.c"
203
204int
205main (int argc, char **argv)
206{
207  mpfr_t x;
208
209  tests_start_mpfr ();
210
211  special ();
212
213  check_inexact ();
214
215  check("1.0", 3, MPFR_RNDN, "3.3333333333333331483e-1");
216  check("1.0", 3, MPFR_RNDZ, "3.3333333333333331483e-1");
217  check("1.0", 3, MPFR_RNDU, "3.3333333333333337034e-1");
218  check("1.0", 3, MPFR_RNDD, "3.3333333333333331483e-1");
219  check("1.0", 2116118, MPFR_RNDN, "4.7256343927890600483e-7");
220  check("1.098612288668109782", 5, MPFR_RNDN, "0.21972245773362195087");
221
222  mpfr_init2 (x, 53);
223  mpfr_set_ui (x, 3, MPFR_RNDD);
224  mpfr_log (x, x, MPFR_RNDD);
225  mpfr_div_ui (x, x, 5, MPFR_RNDD);
226  if (mpfr_cmp_str1 (x, "0.21972245773362189536"))
227    {
228      printf ("Error in mpfr_div_ui for x=ln(3), u=5\n");
229      exit (1);
230    }
231  mpfr_clear (x);
232
233  test_generic_ui (2, 200, 100);
234
235  tests_end_mpfr ();
236  return 0;
237}
238