1 /* trootofunity -- test file for mpc_rootofunity.
2
3 Copyright (C) 2012, 2016 INRIA
4
5 This file is part of GNU MPC.
6
7 GNU MPC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU Lesser General Public License as published by the
9 Free Software Foundation; either version 3 of the License, or (at your
10 option) any later version.
11
12 GNU MPC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
14 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
15 more details.
16
17 You should have received a copy of the GNU Lesser General Public License
18 along with this program. If not, see http://www.gnu.org/licenses/ .
19 */
20
21 #include "mpc-tests.h"
22
23 #define MPC_FUNCTION_CALL \
24 P[0].mpc_inex = mpc_rootofunity (P[1].mpc, P[2].ui, P[3].ui, P[4].mpc_rnd)
25
26 #include "data_check.tpl"
27 #include "tgeneric.tpl"
28
29 static void
check(unsigned long int n)30 check (unsigned long int n)
31 /* checks whether zeta_n^n = 1, which is somewhat dangerous in floating
32 point */
33 {
34 mpc_t z, zero;
35 mpfr_prec_t prec;
36
37 mpc_init2 (z, 2);
38 mpc_init2 (zero, 2);
39
40 for (prec = 2*n; prec < 1000; prec = (mpfr_prec_t) (prec * 1.1 + 1)) {
41 mpc_set_prec (z, prec);
42 mpc_set_prec (zero, prec);
43
44 mpc_rootofunity (z, n, 1, MPC_RNDNN);
45 mpc_pow_ui (zero, z, n, MPC_RNDNN);
46 mpc_sub_ui (zero, zero, 1u, MPC_RNDNN);
47 if (MPC_MAX (mpfr_get_exp (mpc_realref (zero)), mpfr_get_exp (mpc_imagref (zero)))
48 > - ((long int) prec - (long int) n)) {
49 fprintf (stderr, "rootofunity too imprecise for n=%lu\n", n);
50 MPC_OUT (z);
51 MPC_OUT (zero);
52 exit (1);
53 }
54 }
55
56 mpc_clear (z);
57 mpc_clear (zero);
58 }
59
60
61 int
main(void)62 main (void)
63 {
64 unsigned long int n;
65
66 for (n = 1; n < 10000; n += 10)
67 check (n);
68
69 test_start ();
70
71 data_check_template ("rootofunity.dsc", "rootofunity.dat");
72
73 /* Avoid checking roots of unity of high order at very low precision,
74 so start only at 20. */
75 tgeneric_template ("rootofunity.dsc", 20, 512, 7, 256);
76
77 test_end ();
78
79 return 0;
80 }
81