1 /* specfunc/gsl_sf_log.h
2 *
3 * Copyright (C) 1996, 1997, 1998, 1999, 2000 Gerard Jungman
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or (at
8 * your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18 */
19
20 /* Author: G. Jungman */
21
22 #ifndef __GSL_SF_LOG_H__
23 #define __GSL_SF_LOG_H__
24
25 #include <gsl/gsl_sf_result.h>
26
27 #undef __BEGIN_DECLS
28 #undef __END_DECLS
29 #ifdef __cplusplus
30 # define __BEGIN_DECLS extern "C" {
31 # define __END_DECLS }
32 #else
33 # define __BEGIN_DECLS /* empty */
34 # define __END_DECLS /* empty */
35 #endif
36
37 __BEGIN_DECLS
38
39
40 /* Provide a logarithm function with GSL semantics.
41 *
42 * exceptions: GSL_EDOM
43 */
44 int gsl_sf_log_e(const double x, gsl_sf_result * result);
45 double gsl_sf_log(const double x);
46
47
48 /* Log(|x|)
49 *
50 * exceptions: GSL_EDOM
51 */
52 int gsl_sf_log_abs_e(const double x, gsl_sf_result * result);
53 double gsl_sf_log_abs(const double x);
54
55
56 /* Complex Logarithm
57 * exp(lnr + I theta) = zr + I zi
58 * Returns argument in [-pi,pi].
59 *
60 * exceptions: GSL_EDOM
61 */
62 int gsl_sf_complex_log_e(const double zr, const double zi, gsl_sf_result * lnr, gsl_sf_result * theta);
63
64
65 /* Log(1 + x)
66 *
67 * exceptions: GSL_EDOM
68 */
69 int gsl_sf_log_1plusx_e(const double x, gsl_sf_result * result);
70 double gsl_sf_log_1plusx(const double x);
71
72
73 /* Log(1 + x) - x
74 *
75 * exceptions: GSL_EDOM
76 */
77 int gsl_sf_log_1plusx_mx_e(const double x, gsl_sf_result * result);
78 double gsl_sf_log_1plusx_mx(const double x);
79
80
81 #if HAVE_EXTERN_INLINE
82 extern inline
83 int
gsl_sf_log_e(const double x,gsl_sf_result * result)84 gsl_sf_log_e(const double x, gsl_sf_result * result)
85 {
86 /* CHECK_POINTER(result) */
87
88 if(x <= 0.0) {
89 result->val = GSL_NAN;
90 result->err = GSL_NAN;
91 GSL_ERROR ("domain error", GSL_EDOM);
92 }
93 else {
94 result->val = log(x);
95 result->err = 2.0 * GSL_DBL_EPSILON * fabs(result->val);
96 return GSL_SUCCESS;
97 }
98 }
99 extern inline
100 int
gsl_sf_log_abs_e(const double x,gsl_sf_result * result)101 gsl_sf_log_abs_e(const double x, gsl_sf_result * result)
102 {
103 /* CHECK_POINTER(result) */
104
105 if(x == 0.0) {
106 result->val = GSL_NAN;
107 result->err = GSL_NAN;
108 GSL_ERROR ("domain error", GSL_EDOM);
109 }
110 else {
111 result->val = log(fabs(x));
112 result->err = 2.0 * GSL_DBL_EPSILON * fabs(result->val);
113 return GSL_SUCCESS;
114 }
115 }
116 #endif /* HAVE_EXTERN_INLINE */
117
118
119 __END_DECLS
120
121 #endif /* __GSL_SF_LOG_H__ */
122