1 /* Test mpz_invert.
2
3 Copyright 1991, 1993, 1994, 1996, 1997, 2000-2005, 2008, 2009, 2012, 2014 Free
4 Software Foundation, Inc.
5
6 This file is part of the GNU MP Library test suite.
7
8 The GNU MP Library test suite is free software; you can redistribute it
9 and/or modify it under the terms of the GNU General Public License as
10 published by the Free Software Foundation; either version 3 of the License,
11 or (at your option) any later version.
12
13 The GNU MP Library test suite is distributed in the hope that it will be
14 useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
16 Public License for more details.
17
18 You should have received a copy of the GNU General Public License along with
19 the GNU MP Library test suite. If not, see https://www.gnu.org/licenses/. */
20
21 #include <stdio.h>
22 #include <stdlib.h>
23
24 #include "gmp-impl.h"
25 #include "tests.h"
26
27 int
main(int argc,char ** argv)28 main (int argc, char **argv)
29 {
30 mpz_t a, m, ainv, t;
31 int test, r;
32 gmp_randstate_ptr rands;
33 mpz_t bs;
34 unsigned long bsi, size_range;
35 int reps = 1000;
36
37 tests_start ();
38 TESTS_REPS (reps, argv, argc);
39
40 rands = RANDS;
41
42 mpz_init (bs);
43 mpz_init (a);
44 mpz_init (m);
45 mpz_init (ainv);
46 mpz_init (t);
47
48 for (test = 0; test < reps; test++)
49 {
50 mpz_urandomb (bs, rands, 32);
51 size_range = mpz_get_ui (bs) % 16 + 2;
52
53 mpz_urandomb (bs, rands, size_range);
54 mpz_rrandomb (a, rands, mpz_get_ui (bs));
55 do {
56 mpz_urandomb (bs, rands, size_range);
57 mpz_rrandomb (m, rands, mpz_get_ui (bs));
58 } while (mpz_sgn (m) == 0);
59
60 mpz_urandomb (bs, rands, 8);
61 bsi = mpz_get_ui (bs);
62
63 if ((bsi & 1) != 0)
64 mpz_neg (a, a);
65 if ((bsi & 2) != 0)
66 mpz_neg (m, m);
67
68 r = mpz_invert (ainv, a, m);
69 if (r != 0)
70 {
71 MPZ_CHECK_FORMAT (ainv);
72
73 if (mpz_cmp_ui (ainv, 0) < 0 || mpz_cmpabs (ainv, m) >= 0)
74 {
75 fprintf (stderr, "ERROR in test %d\n", test);
76 gmp_fprintf (stderr, "Inverse out of range.\n");
77 gmp_fprintf (stderr, "a = %Zx\n", a);
78 gmp_fprintf (stderr, "1/a = %Zx\n", ainv);
79 gmp_fprintf (stderr, "m = %Zx\n", m);
80 abort ();
81 }
82
83 mpz_mul (t, ainv, a);
84 mpz_mod (t, t, m);
85
86 if (mpz_cmp_ui (t, mpz_cmpabs_ui (m, 1) != 0) != 0)
87 {
88 fprintf (stderr, "ERROR in test %d\n", test);
89 gmp_fprintf (stderr, "a^(-1)*a != 1 (mod m)\n");
90 gmp_fprintf (stderr, "a = %Zx\n", a);
91 gmp_fprintf (stderr, "m = %Zx\n", m);
92 abort ();
93 }
94 }
95 else /* Inverse deos not exist */
96 {
97 mpz_gcd (t, a, m);
98 if (mpz_cmp_ui (t, 1) == 0)
99 {
100 fprintf (stderr, "ERROR in test %d\n", test);
101 gmp_fprintf (stderr, "Inverse exists, but was not found.\n");
102 gmp_fprintf (stderr, "a = %Zx\n", a);
103 gmp_fprintf (stderr, "m = %Zx\n", m);
104 abort ();
105 }
106 }
107 }
108
109 mpz_clear (bs);
110 mpz_clear (a);
111 mpz_clear (m);
112 mpz_clear (ainv);
113 mpz_clear (t);
114
115 tests_end ();
116 exit (0);
117 }
118