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| author | Mark Dickinson <dickinsm@gmail.com> | 2008-04-19 18:51:48 (GMT) |
|---|---|---|
| committer | Mark Dickinson <dickinsm@gmail.com> | 2008-04-19 18:51:48 (GMT) |
| commit | e941d97d123377c9e2c9f4cfec2e9827df0467c4 (patch) | |
| tree | bff8904bbe7b9ea8d4c6b09fc6a84cb7e6ab1842 /Modules/mathmodule.c | |
| parent | c7bef374029a69719d8ba7f7d5ed9b056b2d0457 (diff) | |
| download | cpython-e941d97d123377c9e2c9f4cfec2e9827df0467c4.zip cpython-e941d97d123377c9e2c9f4cfec2e9827df0467c4.tar.gz cpython-e941d97d123377c9e2c9f4cfec2e9827df0467c4.tar.bz2 | |
Additional tests for math.pow, and extra special-case
handling code in math.pow, in the hope of making all
tests pass on the alpha Tru64 buildbot.
Diffstat (limited to 'Modules/mathmodule.c')
| -rw-r--r-- | Modules/mathmodule.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/Modules/mathmodule.c b/Modules/mathmodule.c index 56b52fd..a78b698 100644 --- a/Modules/mathmodule.c +++ b/Modules/mathmodule.c @@ -513,6 +513,7 @@ math_pow(PyObject *self, PyObject *args) { PyObject *ox, *oy; double r, x, y; + int y_is_odd; if (! PyArg_UnpackTuple(args, "pow", 2, 2, &ox, &oy)) return NULL; @@ -523,6 +524,16 @@ math_pow(PyObject *self, PyObject *args) /* 1**x and x**0 return 1., even if x is a NaN or infinity. */ if (x == 1.0 || y == 0.0) return PyFloat_FromDouble(1.); + /* 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; + if (y > 0.) + r = y_is_odd ? x : fabs(x); + else + r = y_is_odd ? copysign(0., x) : 0.; + return PyFloat_FromDouble(r); + } + errno = 0; PyFPE_START_PROTECT("in math_pow", return 0); r = pow(x, y); |