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pymath.h
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1 #ifndef Py_PYMATH_H
2 #define Py_PYMATH_H
3 
4 #include "pyconfig.h" /* include for defines */
5 
6 /**************************************************************************
7 Symbols and macros to supply platform-independent interfaces to mathematical
8 functions and constants
9 **************************************************************************/
10 
11 /* Python provides implementations for copysign, round and hypot in
12  * Python/pymath.c just in case your math library doesn't provide the
13  * functions.
14  *
15  *Note: PC/pyconfig.h defines copysign as _copysign
16  */
17 #ifndef HAVE_COPYSIGN
18 extern double copysign(double, double);
19 #endif
20 
21 #ifndef HAVE_ROUND
22 extern double round(double);
23 #endif
24 
25 #ifndef HAVE_HYPOT
26 extern double hypot(double, double);
27 #endif
28 
29 /* extra declarations */
30 #ifndef _MSC_VER
31 #ifndef __STDC__
32 extern double fmod (double, double);
33 extern double frexp (double, int *);
34 extern double ldexp (double, int);
35 extern double modf (double, double *);
36 extern double pow(double, double);
37 #endif /* __STDC__ */
38 #endif /* _MSC_VER */
39 
40 #ifdef _OSF_SOURCE
41 /* OSF1 5.1 doesn't make these available with XOPEN_SOURCE_EXTENDED defined */
42 extern int finite(double);
43 extern double copysign(double, double);
44 #endif
45 
46 /* High precision defintion of pi and e (Euler)
47  * The values are taken from libc6's math.h.
48  */
49 #ifndef Py_MATH_PIl
50 #define Py_MATH_PIl 3.1415926535897932384626433832795029L
51 #endif
52 #ifndef Py_MATH_PI
53 #define Py_MATH_PI 3.14159265358979323846
54 #endif
55 
56 #ifndef Py_MATH_El
57 #define Py_MATH_El 2.7182818284590452353602874713526625L
58 #endif
59 
60 #ifndef Py_MATH_E
61 #define Py_MATH_E 2.7182818284590452354
62 #endif
63 
64 /* On x86, Py_FORCE_DOUBLE forces a floating-point number out of an x87 FPU
65  register and into a 64-bit memory location, rounding from extended
66  precision to double precision in the process. On other platforms it does
67  nothing. */
68 
69 /* we take double rounding as evidence of x87 usage */
70 #ifndef Py_FORCE_DOUBLE
71 # ifdef X87_DOUBLE_ROUNDING
72 PyAPI_FUNC(double) _Py_force_double(double);
73 # define Py_FORCE_DOUBLE(X) (_Py_force_double(X))
74 # else
75 # define Py_FORCE_DOUBLE(X) (X)
76 # endif
77 #endif
78 
79 #ifdef HAVE_GCC_ASM_FOR_X87
80 PyAPI_FUNC(unsigned short) _Py_get_387controlword(void);
81 PyAPI_FUNC(void) _Py_set_387controlword(unsigned short);
82 #endif
83 
84 /* Py_IS_NAN(X)
85  * Return 1 if float or double arg is a NaN, else 0.
86  * Caution:
87  * X is evaluated more than once.
88  * This may not work on all platforms. Each platform has *some*
89  * way to spell this, though -- override in pyconfig.h if you have
90  * a platform where it doesn't work.
91  * Note: PC/pyconfig.h defines Py_IS_NAN as _isnan
92  */
93 #ifndef Py_IS_NAN
94 #if defined HAVE_DECL_ISNAN && HAVE_DECL_ISNAN == 1
95 #define Py_IS_NAN(X) isnan(X)
96 #else
97 #define Py_IS_NAN(X) ((X) != (X))
98 #endif
99 #endif
100 
101 /* Py_IS_INFINITY(X)
102  * Return 1 if float or double arg is an infinity, else 0.
103  * Caution:
104  * X is evaluated more than once.
105  * This implementation may set the underflow flag if |X| is very small;
106  * it really can't be implemented correctly (& easily) before C99.
107  * Override in pyconfig.h if you have a better spelling on your platform.
108  * Py_FORCE_DOUBLE is used to avoid getting false negatives from a
109  * non-infinite value v sitting in an 80-bit x87 register such that
110  * v becomes infinite when spilled from the register to 64-bit memory.
111  * Note: PC/pyconfig.h defines Py_IS_INFINITY as _isinf
112  */
113 #ifndef Py_IS_INFINITY
114 # if defined HAVE_DECL_ISINF && HAVE_DECL_ISINF == 1
115 # define Py_IS_INFINITY(X) isinf(X)
116 # else
117 # define Py_IS_INFINITY(X) ((X) && \
118  (Py_FORCE_DOUBLE(X)*0.5 == Py_FORCE_DOUBLE(X)))
119 # endif
120 #endif
121 
122 /* Py_IS_FINITE(X)
123  * Return 1 if float or double arg is neither infinite nor NAN, else 0.
124  * Some compilers (e.g. VisualStudio) have intrisics for this, so a special
125  * macro for this particular test is useful
126  * Note: PC/pyconfig.h defines Py_IS_FINITE as _finite
127  */
128 #ifndef Py_IS_FINITE
129 #if defined HAVE_DECL_ISFINITE && HAVE_DECL_ISFINITE == 1
130 #define Py_IS_FINITE(X) isfinite(X)
131 #elif defined HAVE_FINITE
132 #define Py_IS_FINITE(X) finite(X)
133 #else
134 #define Py_IS_FINITE(X) (!Py_IS_INFINITY(X) && !Py_IS_NAN(X))
135 #endif
136 #endif
137 
138 /* HUGE_VAL is supposed to expand to a positive double infinity. Python
139  * uses Py_HUGE_VAL instead because some platforms are broken in this
140  * respect. We used to embed code in pyport.h to try to worm around that,
141  * but different platforms are broken in conflicting ways. If you're on
142  * a platform where HUGE_VAL is defined incorrectly, fiddle your Python
143  * config to #define Py_HUGE_VAL to something that works on your platform.
144  */
145 #ifndef Py_HUGE_VAL
146 #define Py_HUGE_VAL HUGE_VAL
147 #endif
148 
149 /* Py_NAN
150  * A value that evaluates to a NaN. On IEEE 754 platforms INF*0 or
151  * INF/INF works. Define Py_NO_NAN in pyconfig.h if your platform
152  * doesn't support NaNs.
153  */
154 #if !defined(Py_NAN) && !defined(Py_NO_NAN)
155 #define Py_NAN (Py_HUGE_VAL * 0.)
156 #endif
157 
158 /* Py_OVERFLOWED(X)
159  * Return 1 iff a libm function overflowed. Set errno to 0 before calling
160  * a libm function, and invoke this macro after, passing the function
161  * result.
162  * Caution:
163  * This isn't reliable. C99 no longer requires libm to set errno under
164  * any exceptional condition, but does require +- HUGE_VAL return
165  * values on overflow. A 754 box *probably* maps HUGE_VAL to a
166  * double infinity, and we're cool if that's so, unless the input
167  * was an infinity and an infinity is the expected result. A C89
168  * system sets errno to ERANGE, so we check for that too. We're
169  * out of luck if a C99 754 box doesn't map HUGE_VAL to +Inf, or
170  * if the returned result is a NaN, or if a C89 box returns HUGE_VAL
171  * in non-overflow cases.
172  * X is evaluated more than once.
173  * Some platforms have better way to spell this, so expect some #ifdef'ery.
174  *
175  * OpenBSD uses 'isinf()' because a compiler bug on that platform causes
176  * the longer macro version to be mis-compiled. This isn't optimal, and
177  * should be removed once a newer compiler is available on that platform.
178  * The system that had the failure was running OpenBSD 3.2 on Intel, with
179  * gcc 2.95.3.
180  *
181  * According to Tim's checkin, the FreeBSD systems use isinf() to work
182  * around a FPE bug on that platform.
183  */
184 #if defined(__FreeBSD__) || defined(__OpenBSD__)
185 #define Py_OVERFLOWED(X) isinf(X)
186 #else
187 #define Py_OVERFLOWED(X) ((X) != 0.0 && (errno == ERANGE || \
188  (X) == Py_HUGE_VAL || \
189  (X) == -Py_HUGE_VAL))
190 #endif
191 
192 #endif /* Py_PYMATH_H */
Fri Nov 21 2014 12:23:28   doxygen 1.8.3.1

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