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1.1 ohara 1: /* Test file for mpfr_get_d
2:
3: Copyright 1999, 2000, 2001, 2002 Free Software Foundation.
4:
5: This file is part of the MPFR Library.
6:
7: The MPFR Library is free software; you can redistribute it and/or modify
8: it under the terms of the GNU Lesser General Public License as published by
9: the Free Software Foundation; either version 2.1 of the License, or (at your
10: option) any later version.
11:
12: The MPFR Library is distributed in the hope that it will be useful, but
13: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14: or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
15: License for more details.
16:
17: You should have received a copy of the GNU Lesser General Public License
18: along with the MPFR Library; see the file COPYING.LIB. If not, write to
19: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
20: MA 02111-1307, USA. */
21:
22: #include <stdio.h>
23: #include <stdlib.h>
24: #include <float.h>
25: #include "gmp.h"
26: #include "gmp-impl.h"
27: #include "mpfr.h"
28: #include "mpfr-impl.h"
29: #include "mpfr-test.h"
30:
31: int check_denorms _PROTO ((void));
32:
33: int
34: check_denorms ()
35: {
36: mp_rnd_t rnd_mode;
37: mpfr_t x;
38: double d, d2, dd, f;
39: int fail = 0, k, n;
40:
41: mpfr_init2 (x, BITS_PER_MP_LIMB);
42:
43: for (rnd_mode = 0; rnd_mode <= 3; rnd_mode++)
44: {
45: #ifdef MPFR_HAVE_FESETROUND
46: mpfr_set_machine_rnd_mode (rnd_mode);
47: #else
48: if (rnd_mode)
49: break; /* second iteration */
50: rnd_mode = GMP_RNDN;
51: #endif
52: for (k = -17; k <= 17; k += 2)
53: {
54: d = k * DBL_MIN; /* k * 2^(-1022) */
55: f = 1.0;
56: mpfr_set_si (x, k, GMP_RNDN);
57: mpfr_div_2exp (x, x, 1022, GMP_RNDN); /* k * 2^(-1022) */
58: for (n = 0; n <= 58; n++)
59: {
60: d2 = d * f;
61: dd = mpfr_get_d (x, rnd_mode);
62: if (d2 != dd) /* should be k * 2^(-1022-n) for n < 53 */
63: {
64: fprintf (stderr,
65: "Wrong result for %d * 2^(%d), rnd_mode %d\n",
66: k, -1022-n, rnd_mode);
67: fprintf (stderr, "got %.20e instead of %.20e\n", dd, d2);
68: fail = 1;
69: }
70: f *= 0.5;
71: mpfr_div_2exp (x, x, 1, GMP_RNDN);
72: }
73: }
74: }
75:
76: mpfr_clear (x);
77: return fail;
78: }
79:
80: int
81: main (void)
82: {
83:
84: #ifdef MPFR_HAVE_FESETROUND
85:
86: mpfr_t half, x, y;
87: mp_rnd_t rnd_mode;
88:
89: #endif
90:
91: mpfr_test_init ();
92:
93: #ifdef MPFR_HAVE_FESETROUND
94:
95: mpfr_init2(half, 2);
96: mpfr_set_ui(half, 1, GMP_RNDZ);
97: mpfr_div_2ui(half, half, 1, GMP_RNDZ); /* has exponent 0 */
98:
99: mpfr_init2(x, 128);
100: mpfr_init2(y, 128);
101:
102: for (rnd_mode = 0; rnd_mode <= 3; rnd_mode++)
103: {
104: int i, j, si, sj;
105: double di, dj;
106:
107: mpfr_set_machine_rnd_mode (rnd_mode);
108: for (i = 1, di = 0.25; i < 127; i++, di *= 0.5)
109: for (si = 0; si <= 1; si++)
110: {
111: mpfr_div_2ui (x, half, i, GMP_RNDZ);
112: (si ? mpfr_sub : mpfr_add)(x, half, x, GMP_RNDZ);
113: /* x = 1/2 +/- 1/2^(1+i) */
114: for (j = i+1, dj = di * 0.5; j < 128 && j < i+53; j++, dj *= 0.5)
115: for (sj = 0; sj <= 1; sj++)
116: {
117: double c, d, dd;
118: int exp;
119: char *f;
120:
121: mpfr_div_2ui (y, half, j, GMP_RNDZ);
122: (sj ? mpfr_sub : mpfr_add)(y, x, y, GMP_RNDZ);
123: /* y = 1/2 +/- 1/2^(1+i) +/- 1/2^(1+j) */
124: exp = (LONG_RAND() % 47) - 23;
125: mpfr_mul_2si (y, y, exp, GMP_RNDZ);
126: if (mpfr_inexflag_p())
127: {
128: fprintf(stderr, "Error in tget_d: inexact flag for "
129: "(i,si,j,sj,rnd,exp) = (%d,%d,%d,%d,%d,%d)\n",
130: i, si, j, sj, rnd_mode, exp);
131: exit(1);
132: }
133: dd = si != sj ? di - dj : di + dj;
134: d = si ? 0.5 - dd : 0.5 + dd;
135: if ((LONG_RAND() / 1024) & 1)
136: {
137: c = mpfr_get_d (y, rnd_mode);
138: f = "mpfr_get_d";
139: }
140: else
141: {
142: exp = (LONG_RAND() % 47) - 23;
143: c = mpfr_get_d3 (y, exp, rnd_mode);
144: f = "mpfr_get_d3";
145: if (si) /* then real d < 0.5 */
146: d *= sj && i == 1 ? 4 : 2; /* normalize real d */
147: }
148: if (exp > 0)
149: d *= 1 << exp;
150: if (exp < 0)
151: d /= 1 << -exp;
152: if (c != d)
153: {
154: fprintf (stderr, "Error in tget_d (%s) for "
155: "(i,si,j,sj,rnd,exp) = (%d,%d,%d,%d,%d,%d)\n"
156: "got %.25Le instead of %.25Le\n"
157: "Difference: %.19e\n",
158: f, i, si, j, sj, rnd_mode, exp,
159: (long double) c, (long double) d, d - c);
160: exit (1);
161: }
162: }
163: }
164: }
165:
166: mpfr_clear(half);
167: mpfr_clear(x);
168: mpfr_clear(y);
169:
170: #endif
171:
172: if (check_denorms ())
173: exit (1);
174:
175: return 0;
176: }