cpython/Modules/mathmodule.c

/***********************************************************
Copyright (c) 2000, BeOpen.com.
Copyright (c) 1995-2000, Corporation for National Research Initiatives.
Copyright (c) 1990-1995, Stichting Mathematisch Centrum.
All rights reserved.

See the file "Misc/COPYRIGHT" for information on usage and
redistribution of this file, and for a DISCLAIMER OF ALL WARRANTIES.
******************************************************************/

/* Math module -- standard C math library functions, pi and e */

#include "Python.h"

#include "mymath.h"

#ifndef _MSC_VER
#ifndef __STDC__
extern double fmod Py_PROTO((double, double));
extern double frexp Py_PROTO((double, int *));
extern double ldexp Py_PROTO((double, int));
extern double modf Py_PROTO((double, double *));
#endif /* __STDC__ */
#endif /* _MSC_VER */


#ifdef i860
/* Cray APP has bogus definition of HUGE_VAL in <math.h> */
#undef HUGE_VAL
#endif

#ifdef HUGE_VAL
#define CHECK(x) if (errno != 0) ; \
	else if (-HUGE_VAL <= (x) && (x) <= HUGE_VAL) ; \
	else errno = ERANGE
#else
#define CHECK(x) /* Don't know how to check */
#endif

static PyObject *
math_error()
{
	if (errno == EDOM)
		PyErr_SetString(PyExc_ValueError, "math domain error");
	else if (errno == ERANGE)
		PyErr_SetString(PyExc_OverflowError, "math range error");
	else
                /* Unexpected math error */
		PyErr_SetFromErrno(PyExc_ValueError);
	return NULL;
}

static PyObject *
math_1(args, func)
	PyObject *args;
	double (*func) Py_FPROTO((double));
{
	double x;
	if (!  PyArg_Parse(args, "d", &x))
		return NULL;
	errno = 0;
	PyFPE_START_PROTECT("in math_1", return 0)
	x = (*func)(x);
	PyFPE_END_PROTECT(x)
	CHECK(x);
	if (errno != 0)
		return math_error();
	else
		return PyFloat_FromDouble(x);
}

static PyObject *
math_2(args, func)
	PyObject *args;
	double (*func) Py_FPROTO((double, double));
{
	double x, y;
	if (! PyArg_Parse(args, "(dd)", &x, &y))
		return NULL;
	errno = 0;
	PyFPE_START_PROTECT("in math_2", return 0)
	x = (*func)(x, y);
	PyFPE_END_PROTECT(x)
	CHECK(x);
	if (errno != 0)
		return math_error();
	else
		return PyFloat_FromDouble(x);
}

#define FUNC1(stubname, func, docstring_name, docstring) \
	static PyObject * stubname(self, args) PyObject *self, *args; { \
		return math_1(args, func); \
	}\
        static char docstring_name [] = docstring;

#define FUNC2(stubname, func, docstring_name, docstring) \
	static PyObject * stubname(self, args) PyObject *self, *args; { \
		return math_2(args, func); \
	}\
        static char docstring_name [] = docstring;

FUNC1(math_acos, acos, math_acos_doc,
      "acos(x)\n\nReturn the arc cosine of x.")
FUNC1(math_asin, asin, math_asin_doc,
      "asin(x)\n\nReturn the arc sine of x.")
FUNC1(math_atan, atan, math_atan_doc,
      "atan(x)\n\nReturn the arc tangent of x.")
FUNC2(math_atan2, atan2, math_atan2_doc,
      "atan2(y, x)\n\nReturn atan(y/x).")
FUNC1(math_ceil, ceil, math_ceil_doc,
      "ceil(x)\n\nReturn the ceiling of x as a real.")
FUNC1(math_cos, cos, math_cos_doc,
      "cos(x)\n\nReturn the cosine of x.")
FUNC1(math_cosh, cosh, math_cosh_doc,
      "cosh(x)\n\nReturn the hyperbolic cosine of x.")
FUNC1(math_exp, exp, math_exp_doc,
      "exp(x)\n\nReturn e raised to the power of x.")
FUNC1(math_fabs, fabs, math_fabs_doc,
      "fabs(x)\n\nReturn the absolute value of the real x.")
FUNC1(math_floor, floor, math_floor_doc,
      "floor(x)\n\nReturn the floor of x as a real.")
FUNC2(math_fmod, fmod, math_fmod_doc,
      "fmod(x,y)\n\nReturn x % y.")
FUNC2(math_hypot, hypot, math_hypot_doc,
      "hypot(x,y)\n\nReturn the Euclidean distance, sqrt(x*x + y*y).")
FUNC1(math_log, log, math_log_doc,
      "log(x)\n\nReturn the natural logarithm of x.")
FUNC1(math_log10, log10, math_log10_doc,
      "log10(x)\n\nReturn the base-10 logarithm of x.")
#ifdef MPW_3_1 /* This hack is needed for MPW 3.1 but not for 3.2 ... */
FUNC2(math_pow, power, math_pow_doc,
      "power(x,y)\n\nReturn x**y.")
#else
FUNC2(math_pow, pow, math_pow_doc,
      "pow(x,y)\n\nReturn x**y.")
#endif
#ifdef HAVE_RINT
FUNC1(math_rint, rint, math_rint_doc,
      "rint(x)\n\nReturn the integer nearest to x as a real.")
#endif
FUNC1(math_sin, sin, math_sin_doc,
      "sin(x)\n\nReturn the sine of x.")
FUNC1(math_sinh, sinh, math_sinh_doc,
      "sinh(x)\n\nReturn the hyperbolic sine of x.")
FUNC1(math_sqrt, sqrt, math_sqrt_doc,
      "sqrt(x)\n\nReturn the square root of x.")
FUNC1(math_tan, tan, math_tan_doc,
      "tan(x)\n\nReturn the tangent of x.")
FUNC1(math_tanh, tanh, math_tanh_doc,
      "tanh(x)\n\nReturn the hyperbolic tangent of x.")


static PyObject *
math_frexp(self, args)
	PyObject *self;
	PyObject *args;
{
	double x;
	int i;
	if (! PyArg_Parse(args, "d", &x))
		return NULL;
	errno = 0;
	x = frexp(x, &i);
	CHECK(x);
	if (errno != 0)
		return math_error();
	return Py_BuildValue("(di)", x, i);
}

static char math_frexp_doc [] =
"frexp(x)\n\
\n\
Return the matissa and exponent of x, as pair (m, e).\n\
m is a float and e is an int, such that x = m * 2.**e.\n\
If x is 0, m and e are both 0.  Else 0.5 <= abs(m) < 1.0.";


static PyObject *
math_ldexp(self, args)
	PyObject *self;
	PyObject *args;
{
	double x;
	int exp;
	if (! PyArg_Parse(args, "(di)", &x, &exp))
		return NULL;
	errno = 0;
	PyFPE_START_PROTECT("ldexp", return 0)
	x = ldexp(x, exp);
	PyFPE_END_PROTECT(x)
	CHECK(x);
	if (errno != 0)
		return math_error();
	else
		return PyFloat_FromDouble(x);
}

static char math_ldexp_doc [] = 
"ldexp_doc(x, i)\n\
\n\
Return x * (2**i).";


static PyObject *
math_modf(self, args)
	PyObject *self;
	PyObject *args;
{
	double x, y;
	if (! PyArg_Parse(args, "d", &x))
		return NULL;
	errno = 0;
#ifdef MPW /* MPW C modf expects pointer to extended as second argument */
{
	extended e;
	x = modf(x, &e);
	y = e;
}
#else
	x = modf(x, &y);
#endif
	CHECK(x);
	if (errno != 0)
		return math_error();
	return Py_BuildValue("(dd)", x, y);
}

static char math_modf_doc [] =
"modf(x)\n\
\n\
Return the fractional and integer parts of x. Both results carry the sign\n\
of x.  The integer part is returned as a real.";


static PyMethodDef math_methods[] = {
	{"acos",	math_acos,	0,	math_acos_doc},
	{"asin",	math_asin,	0,	math_asin_doc},
	{"atan",	math_atan,	0,	math_atan_doc},
	{"atan2",	math_atan2,	0,	math_atan2_doc},
	{"ceil",	math_ceil,	0,	math_ceil_doc},
	{"cos",		math_cos,	0,	math_cos_doc},
	{"cosh",	math_cosh,	0,	math_cosh_doc},
	{"exp",		math_exp,	0,	math_exp_doc},
	{"fabs",	math_fabs,	0,	math_fabs_doc},
	{"floor",	math_floor,	0,	math_floor_doc},
	{"fmod",	math_fmod,	0,	math_fmod_doc},
	{"frexp",	math_frexp,	0,	math_frexp_doc},
	{"hypot",	math_hypot,	0,	math_hypot_doc},
	{"ldexp",	math_ldexp,	0,	math_ldexp_doc},
	{"log",		math_log,	0,	math_log_doc},
	{"log10",	math_log10,	0,	math_log10_doc},
	{"modf",	math_modf,	0,	math_modf_doc},
	{"pow",		math_pow,	0,	math_pow_doc},
#ifdef HAVE_RINT
	{"rint",	math_rint,	0,	math_rint_doc},
#endif
	{"sin",		math_sin,	0,	math_sin_doc},
	{"sinh",	math_sinh,	0,	math_sinh_doc},
	{"sqrt",	math_sqrt,	0,	math_sqrt_doc},
	{"tan",		math_tan,	0,	math_tan_doc},
	{"tanh",	math_tanh,	0,	math_tanh_doc},
	{NULL,		NULL}		/* sentinel */
};


static char module_doc [] =
"This module is always available.  It provides access to the\n\
mathematical functions defined by the C standard.";

DL_EXPORT(void)
initmath()
{
	PyObject *m, *d, *v;
	
	m = Py_InitModule3("math", math_methods, module_doc);
	d = PyModule_GetDict(m);

        if (!(v = PyFloat_FromDouble(atan(1.0) * 4.0)))
                goto finally;
	if (PyDict_SetItemString(d, "pi", v) < 0)
                goto finally;
	Py_DECREF(v);

        if (!(v = PyFloat_FromDouble(exp(1.0))))
                goto finally;
	if (PyDict_SetItemString(d, "e", v) < 0)
                goto finally;
	Py_DECREF(v);
	return;

  finally:
        Py_FatalError("can't initialize math module");
}