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Additional special-case handling for math.pow. 

Windows/VS2008 doesn't like (-1)**(+-inf).
This commit is contained in:
Mark Dickinson 2008-04-19 19:41:52 +00:00
parent 53be57e8f8
commit a1293eb65f
1 changed files with 13 additions and 6 deletions
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19
Modules/mathmodule.c
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@ -521,9 +521,19 @@ math_pow(PyObject *self, PyObject *args)
y = PyFloat_AsDouble(oy);
if ((x == -1.0 || y == -1.0) && PyErr_Occurred())
return NULL;
/* 1**x and x**0 return 1., even if x is a NaN or infinity. */
if (x == 1.0 || y == 0.0)
/* deal directly with various special cases, to cope with problems on
various platforms whose semantics don't exactly match C99 */
/* 1**x, x**0, and (-1)**(+-infinity) return 1., even if x is NaN or
an infinity. */
if (x == 1. || y == 0. || (x == -1. && Py_IS_INFINITY(y)))
return PyFloat_FromDouble(1.);
/* otherwise, return a NaN if either input was a NaN */
if (Py_IS_NAN(x))
return PyFloat_FromDouble(x);
if (Py_IS_NAN(y))
return PyFloat_FromDouble(y);
/* inf ** (nonzero, non-NaN) is one of +-0, +-infinity */
if (Py_IS_INFINITY(x) && !Py_IS_NAN(y)) {
y_is_odd = Py_IS_FINITE(y) && fmod(fabs(y), 2.0) == 1.0;
@ -539,10 +549,7 @@ math_pow(PyObject *self, PyObject *args)
r = pow(x, y);
PyFPE_END_PROTECT(r);
if (Py_IS_NAN(r)) {
if (!Py_IS_NAN(x) && !Py_IS_NAN(y))
errno = EDOM;
else
errno = 0;
errno = EDOM;
}
/* an infinite result arises either from: