xref: /netbsd-src/external/lgpl3/gmp/dist/mini-gmp/tests/t-root.c (revision 4d5abbe83f525258eb479e5fca29f25cb943f379)
1 /*
2 
3 Copyright 2012, 2013 Free Software Foundation, Inc.
4 
5 This file is part of the GNU MP Library test suite.
6 
7 The GNU MP Library test suite is free software; you can redistribute it
8 and/or modify it under the terms of the GNU General Public License as
9 published by the Free Software Foundation; either version 3 of the License,
10 or (at your option) any later version.
11 
12 The GNU MP Library test suite is distributed in the hope that it will be
13 useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
15 Public License for more details.
16 
17 You should have received a copy of the GNU General Public License along with
18 the GNU MP Library test suite.  If not, see http://www.gnu.org/licenses/.  */
19 
20 #include <limits.h>
21 #include <stdlib.h>
22 #include <stdio.h>
23 
24 #include "testutils.h"
25 
26 #define MAXBITS 400
27 #define COUNT 10000
28 
29 static void
30 dump (const char *label, const mpz_t x)
31 {
32   char *buf = mpz_get_str (NULL, 16, x);
33   fprintf (stderr, "%s: %s\n", label, buf);
34   testfree (buf);
35 }
36 
37 /* Called when s is supposed to be floor(root(u,z)), and r = u - s^z */
38 static int
39 rootrem_valid_p (const mpz_t u, const mpz_t s, const mpz_t r, unsigned long z)
40 {
41   mpz_t t;
42 
43   mpz_init (t);
44   if (mpz_fits_ulong_p (s))
45     mpz_ui_pow_ui (t, mpz_get_ui (s), z);
46   else
47     mpz_pow_ui (t, s, z);
48   mpz_sub (t, u, t);
49   if (mpz_sgn (t) != mpz_sgn(u) || mpz_cmp (t, r) != 0)
50     {
51       mpz_clear (t);
52       return 0;
53     }
54   if (mpz_sgn (s) > 0)
55     mpz_add_ui (t, s, 1);
56   else
57     mpz_sub_ui (t, s, 1);
58   mpz_pow_ui (t, t, z);
59   if (mpz_cmpabs (t, u) <= 0)
60     {
61       mpz_clear (t);
62       return 0;
63     }
64 
65   mpz_clear (t);
66   return 1;
67 }
68 
69 void
70 testmain (int argc, char **argv)
71 {
72   unsigned i;
73   unsigned long e;
74   mpz_t u, s, r, bs;
75 
76   mpz_init (u);
77   mpz_init (s);
78   mpz_init (r);
79   mpz_init (bs);
80 
81   for (i = 0; i < COUNT; i++)
82     {
83       mini_rrandomb (u, MAXBITS);
84       mini_rrandomb (bs, 12);
85       e = mpz_getlimbn (bs, 0) % mpz_sizeinbase (u, 2) + 2;
86       if ((e & 1) && (mpz_getlimbn (bs, 0) & (1L<<10)))
87 	mpz_neg (u, u);
88       mpz_rootrem (s, r, u, e);
89 
90       if (!rootrem_valid_p (u, s, r, e))
91 	{
92 	  fprintf (stderr, "mpz_rootrem(%lu-th) failed:\n", e);
93 	  dump ("u", u);
94 	  dump ("root", s);
95 	  dump ("rem", r);
96 	  abort ();
97 	}
98     }
99   mpz_clear (bs);
100   mpz_clear (u);
101   mpz_clear (s);
102   mpz_clear (r);
103 }
104