Include/pymath.h

   1 #ifndef Py_PYMATH_H
   2 #define Py_PYMATH_H
   3
   4 #include "pyconfig.h" /* include for defines */
   5
   6 #ifdef HAVE_STDINT_H
   7 #include <stdint.h>
   8 #endif
   9
  10 /**************************************************************************
  11 Symbols and macros to supply platform-independent interfaces to mathematical
  12 functions and constants
  13 **************************************************************************/
  14
  15 /* Python provides implementations for copysign, acosh, asinh, atanh,
  16  * log1p and hypot in Python/pymath.c just in case your math library doesn't
  17  * provide the functions.
  18  *
  19  *Note: PC/pyconfig.h defines copysign as _copysign
  20  */
  21 #ifndef HAVE_COPYSIGN
  22 extern double copysign(double, double);
  23 #endif
  24
  25 #ifndef HAVE_ROUND
  26 extern double round(double);
  27 #endif
  28
  29 #ifndef HAVE_ACOSH
  30 extern double acosh(double);
  31 #endif
  32
  33 #ifndef HAVE_ASINH
  34 extern double asinh(double);
  35 #endif
  36
  37 #ifndef HAVE_ATANH
  38 extern double atanh(double);
  39 #endif
  40
  41 #ifndef HAVE_LOG1P
  42 extern double log1p(double);
  43 #endif
  44
  45 #ifndef HAVE_HYPOT
  46 extern double hypot(double, double);
  47 #endif
  48
  49 /* extra declarations */
  50 #ifndef _MSC_VER
  51 #ifndef __STDC__
  52 extern double fmod (double, double);
  53 extern double frexp (double, int *);
  54 extern double ldexp (double, int);
  55 extern double modf (double, double *);
  56 extern double pow(double, double);
  57 #endif /* __STDC__ */
  58 #endif /* _MSC_VER */
  59
  60 #ifdef _OSF_SOURCE
  61 /* OSF1 5.1 doesn't make these available with XOPEN_SOURCE_EXTENDED defined */
  62 extern int finite(double);
  63 extern double copysign(double, double);
  64 #endif
  65
  66 /* High precision defintion of pi and e (Euler)
  67  * The values are taken from libc6's math.h.
  68  */
  69 #ifndef Py_MATH_PIl
  70 #define Py_MATH_PIl 3.1415926535897932384626433832795029L
  71 #endif
  72 #ifndef Py_MATH_PI
  73 #define Py_MATH_PI 3.14159265358979323846
  74 #endif
  75
  76 #ifndef Py_MATH_El
  77 #define Py_MATH_El 2.7182818284590452353602874713526625L
  78 #endif
  79
  80 #ifndef Py_MATH_E
  81 #define Py_MATH_E 2.7182818284590452354
  82 #endif
  83
  84 /* On x86, Py_FORCE_DOUBLE forces a floating-point number out of an x87 FPU
  85    register and into a 64-bit memory location, rounding from extended
  86    precision to double precision in the process.  On other platforms it does
  87    nothing. */
  88
  89 /* we take double rounding as evidence of x87 usage */
  90 #ifndef Py_FORCE_DOUBLE
  91 #  ifdef X87_DOUBLE_ROUNDING
  92 PyAPI_FUNC(double) _Py_force_double(double);
  93 #    define Py_FORCE_DOUBLE(X) (_Py_force_double(X))
  94 #  else
  95 #    define Py_FORCE_DOUBLE(X) (X)
  96 #  endif
  97 #endif
  98
  99 /* Py_IS_NAN(X)
 100  * Return 1 if float or double arg is a NaN, else 0.
 101  * Caution:
 102  *     X is evaluated more than once.
 103  *     This may not work on all platforms.  Each platform has *some*
 104  *     way to spell this, though -- override in pyconfig.h if you have
 105  *     a platform where it doesn't work.
 106  * Note: PC/pyconfig.h defines Py_IS_NAN as _isnan
 107  */
 108 #ifndef Py_IS_NAN
 109 #if defined HAVE_DECL_ISNAN && HAVE_DECL_ISNAN == 1
 110 #define Py_IS_NAN(X) isnan(X)
 111 #else
 112 #define Py_IS_NAN(X) ((X) != (X))
 113 #endif
 114 #endif
 115
 116 /* Py_IS_INFINITY(X)
 117  * Return 1 if float or double arg is an infinity, else 0.
 118  * Caution:
 119  *    X is evaluated more than once.
 120  *    This implementation may set the underflow flag if |X| is very small;
 121  *    it really can't be implemented correctly (& easily) before C99.
 122  *    Override in pyconfig.h if you have a better spelling on your platform.
 123  *  Py_FORCE_DOUBLE is used to avoid getting false negatives from a
 124  *    non-infinite value v sitting in an 80-bit x87 register such that
 125  *    v becomes infinite when spilled from the register to 64-bit memory.
 126  * Note: PC/pyconfig.h defines Py_IS_INFINITY as _isinf
 127  */
 128 #ifndef Py_IS_INFINITY
 129 #  if defined HAVE_DECL_ISINF && HAVE_DECL_ISINF == 1
 130 #    define Py_IS_INFINITY(X) isinf(X)
 131 #  else
 132 #    define Py_IS_INFINITY(X) ((X) &&                                   \
 133                                (Py_FORCE_DOUBLE(X)*0.5 == Py_FORCE_DOUBLE(X)))
 134 #  endif
 135 #endif
 136
 137 /* Py_IS_FINITE(X)
 138  * Return 1 if float or double arg is neither infinite nor NAN, else 0.
 139  * Some compilers (e.g. VisualStudio) have intrisics for this, so a special
 140  * macro for this particular test is useful
 141  * Note: PC/pyconfig.h defines Py_IS_FINITE as _finite
 142  */
 143 #ifndef Py_IS_FINITE
 144 #if defined HAVE_DECL_ISFINITE && HAVE_DECL_ISFINITE == 1
 145 #define Py_IS_FINITE(X) isfinite(X)
 146 #elif defined HAVE_FINITE
 147 #define Py_IS_FINITE(X) finite(X)
 148 #else
 149 #define Py_IS_FINITE(X) (!Py_IS_INFINITY(X) && !Py_IS_NAN(X))
 150 #endif
 151 #endif
 152
 153 /* HUGE_VAL is supposed to expand to a positive double infinity.  Python
 154  * uses Py_HUGE_VAL instead because some platforms are broken in this
 155  * respect.  We used to embed code in pyport.h to try to worm around that,
 156  * but different platforms are broken in conflicting ways.  If you're on
 157  * a platform where HUGE_VAL is defined incorrectly, fiddle your Python
 158  * config to #define Py_HUGE_VAL to something that works on your platform.
 159  */
 160 #ifndef Py_HUGE_VAL
 161 #define Py_HUGE_VAL HUGE_VAL
 162 #endif
 163
 164 /* Py_NAN
 165  * A value that evaluates to a NaN. On IEEE 754 platforms INF*0 or
 166  * INF/INF works. Define Py_NO_NAN in pyconfig.h if your platform
 167  * doesn't support NaNs.
 168  */
 169 #if !defined(Py_NAN) && !defined(Py_NO_NAN)
 170 #define Py_NAN (Py_HUGE_VAL * 0.)
 171 #endif
 172
 173 /* Py_OVERFLOWED(X)
 174  * Return 1 iff a libm function overflowed.  Set errno to 0 before calling
 175  * a libm function, and invoke this macro after, passing the function
 176  * result.
 177  * Caution:
 178  *    This isn't reliable.  C99 no longer requires libm to set errno under
 179  *        any exceptional condition, but does require +- HUGE_VAL return
 180  *        values on overflow.  A 754 box *probably* maps HUGE_VAL to a
 181  *        double infinity, and we're cool if that's so, unless the input
 182  *        was an infinity and an infinity is the expected result.  A C89
 183  *        system sets errno to ERANGE, so we check for that too.  We're
 184  *        out of luck if a C99 754 box doesn't map HUGE_VAL to +Inf, or
 185  *        if the returned result is a NaN, or if a C89 box returns HUGE_VAL
 186  *        in non-overflow cases.
 187  *    X is evaluated more than once.
 188  * Some platforms have better way to spell this, so expect some #ifdef'ery.
 189  *
 190  * OpenBSD uses 'isinf()' because a compiler bug on that platform causes
 191  * the longer macro version to be mis-compiled. This isn't optimal, and
 192  * should be removed once a newer compiler is available on that platform.
 193  * The system that had the failure was running OpenBSD 3.2 on Intel, with
 194  * gcc 2.95.3.
 195  *
 196  * According to Tim's checkin, the FreeBSD systems use isinf() to work
 197  * around a FPE bug on that platform.
 198  */
 199 #if defined(__FreeBSD__) || defined(__OpenBSD__)
 200 #define Py_OVERFLOWED(X) isinf(X)
 201 #else
 202 #define Py_OVERFLOWED(X) ((X) != 0.0 && (errno == ERANGE ||    \
 203                                          (X) == Py_HUGE_VAL || \
 204                                          (X) == -Py_HUGE_VAL))
 205 #endif
 206
 207 #endif /* Py_PYMATH_H */