[Python-checkins] r59676 - in python/trunk: Doc/library/math.rst Lib/test/test_math.py Misc/NEWS Modules/mathmodule.c

Thu Jan 3 21:23:15 CET 2008

Author: christian.heimes
Date: Thu Jan 3 21:23:15 2008
New Revision: 59676
Modified:
 python/trunk/Doc/library/math.rst
 python/trunk/Lib/test/test_math.py
 python/trunk/Misc/NEWS
 python/trunk/Modules/mathmodule.c
Log:
Added math.isinf() and math.isnan()
Modified: python/trunk/Doc/library/math.rst
==============================================================================

--- python/trunk/Doc/library/math.rst	(original)
+++ python/trunk/Doc/library/math.rst	Thu Jan 3 21:23:15 2008
@@ -66,6 +66,23 @@
 apart" the internal representation of a float in a portable way.
 
 
+.. function:: isinf(x)
+
+ Checks if the float *x* is positive or negative infinite.
+
+ ..versionadded:: 2.6
+
+
+.. function:: isnan(x)
+
+ Checks if the float *x* is a NaN (not a number). NaNs are part of the
+ IEEE 754 standards. Operation like but not limited to ``inf * 0``, 
+ ``inf / inf`` or any operation involving a NaN, e.g. ``nan * 1``, return
+ a NaN.
+
+ ..versionadded:: 2.6
+
+
 .. function:: ldexp(x, i)
 
 Return ``x * (2**i)``. This is essentially the inverse of function
Modified: python/trunk/Lib/test/test_math.py
==============================================================================
--- python/trunk/Lib/test/test_math.py	(original)
+++ python/trunk/Lib/test/test_math.py	Thu Jan 3 21:23:15 2008
@@ -229,6 +229,22 @@
 self.ftest('tanh(0)', math.tanh(0), 0)
 self.ftest('tanh(1)+tanh(-1)', math.tanh(1)+math.tanh(-1), 0)
 
+ def testIsnan(self):
+ self.assert_(math.isnan(float("nan")))
+ self.assert_(math.isnan(float("inf")* 0.))
+ self.failIf(math.isnan(float("inf")))
+ self.failIf(math.isnan(0.))
+ self.failIf(math.isnan(1.))
+
+ def testIsinf(self):
+ self.assert_(math.isinf(float("inf")))
+ self.assert_(math.isinf(float("-inf")))
+ self.assert_(math.isinf(1E400))
+ self.assert_(math.isinf(-1E400))
+ self.failIf(math.isinf(float("nan")))
+ self.failIf(math.isinf(0.))
+ self.failIf(math.isinf(1.))
+
 # RED_FLAG 16-Oct-2000 Tim
 # While 2.0 is more consistent about exceptions than previous releases, it
 # still fails this part of the test on some platforms. For now, we only
Modified: python/trunk/Misc/NEWS
==============================================================================
--- python/trunk/Misc/NEWS	(original)
+++ python/trunk/Misc/NEWS	Thu Jan 3 21:23:15 2008
@@ -12,6 +12,8 @@
 Core and builtins
 -----------------
 
+- Issue #1640: Added math.isinf() and math.isnan() functions.
+
 - Issue #1726: Remove Python/atof.c from PCBuild/pythoncore.vcproj
 
 - Removed PCbuild8/ directory and added a new build directory for VS 2005
Modified: python/trunk/Modules/mathmodule.c
==============================================================================
--- python/trunk/Modules/mathmodule.c	(original)
+++ python/trunk/Modules/mathmodule.c	Thu Jan 3 21:23:15 2008
@@ -315,9 +315,8 @@
 PyDoc_STRVAR(math_log10_doc,
 "log10(x) -> the base 10 logarithm of x.");
 
-/* XXX(nnorwitz): Should we use the platform M_PI or something more accurate
- like: 3.14159265358979323846264338327950288 */
-static const double degToRad = 3.141592653589793238462643383 / 180.0;
+static const double degToRad = Py_MATH_PI / 180.0;
+static const double radToDeg = 180.0 / Py_MATH_PI;
 
 static PyObject *
 math_degrees(PyObject *self, PyObject *arg)
@@ -325,7 +324,7 @@
 	double x = PyFloat_AsDouble(arg);
 	if (x == -1.0 && PyErr_Occurred())
 		return NULL;
-	return PyFloat_FromDouble(x / degToRad);
+	return PyFloat_FromDouble(x * radToDeg);
 }
 
 PyDoc_STRVAR(math_degrees_doc,
@@ -343,6 +342,33 @@
 PyDoc_STRVAR(math_radians_doc,
 "radians(x) -> converts angle x from degrees to radians");
 
+static PyObject *
+math_isnan(PyObject *self, PyObject *arg)
+{
+	double x = PyFloat_AsDouble(arg);
+	if (x == -1.0 && PyErr_Occurred())
+		return NULL;
+	return PyBool_FromLong((long)Py_IS_NAN(x));
+}
+
+PyDoc_STRVAR(math_isnan_doc,
+"isnan(x) -> bool\n\
+Checks if float x is not a number (NaN)");
+
+static PyObject *
+math_isinf(PyObject *self, PyObject *arg)
+{
+	double x = PyFloat_AsDouble(arg);
+	if (x == -1.0 && PyErr_Occurred())
+		return NULL;
+	return PyBool_FromLong((long)Py_IS_INFINITY(x));
+}
+
+PyDoc_STRVAR(math_isinf_doc,
+"isinf(x) -> bool\n\
+Checks if float x is infinite (positive or negative)");
+
+
 static PyMethodDef math_methods[] = {
 	{"acos",	math_acos,	METH_O,		math_acos_doc},
 	{"asin",	math_asin,	METH_O,		math_asin_doc},
@@ -358,6 +384,8 @@
 	{"fmod",	math_fmod,	METH_VARARGS,	math_fmod_doc},
 	{"frexp",	math_frexp,	METH_O,		math_frexp_doc},
 	{"hypot",	math_hypot,	METH_VARARGS,	math_hypot_doc},
+	{"isinf",	math_isinf,	METH_O,		math_isinf_doc},
+	{"isnan",	math_isnan,	METH_O,		math_isnan_doc},
 	{"ldexp",	math_ldexp,	METH_VARARGS,	math_ldexp_doc},
 	{"log",		math_log,	METH_VARARGS,	math_log_doc},
 	{"log10",	math_log10,	METH_O,		math_log10_doc},
@@ -389,13 +417,13 @@
 	if (d == NULL)
 		goto finally;
 
- if (!(v = PyFloat_FromDouble(atan(1.0) * 4.0)))
+ if (!(v = PyFloat_FromDouble(Py_MATH_PI)))
 goto finally;
 	if (PyDict_SetItemString(d, "pi", v) < 0)
 goto finally;
 	Py_DECREF(v);
 
- if (!(v = PyFloat_FromDouble(exp(1.0))))
+ if (!(v = PyFloat_FromDouble(Py_MATH_E)))
 goto finally;
 	if (PyDict_SetItemString(d, "e", v) < 0)
 goto finally;
