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authorChristian Heimes <christian@cheimes.de>2008-04-21 13:08:03 (GMT)
committerChristian Heimes <christian@cheimes.de>2008-04-21 13:08:03 (GMT)
commite57950fbfef77f327d79a73955b42e3696ecf9f0 (patch)
tree67d0fdaadc4f912bc78626859b802b37ca1696dd /Modules
parent1a3239e94509ac236ee886ce64e6cb0c5a3fea9f (diff)
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Merged revisions 62420-62421,62423-62424 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk ........ r62420 | mark.dickinson | 2008-04-20 20:30:05 +0200 (Sun, 20 Apr 2008) | 3 lines Even more fixes for alpha Tru64, this time for the phase and polar methods. ........ r62421 | mark.dickinson | 2008-04-20 22:38:48 +0200 (Sun, 20 Apr 2008) | 2 lines Add test for tanh(-0.) == -0. on IEEE 754 systems ........ r62423 | amaury.forgeotdarc | 2008-04-20 23:02:21 +0200 (Sun, 20 Apr 2008) | 3 lines Correct an apparent refleak in test_pkgutil: zipimport._zip_directory_cache contains info for all processed zip files, even when they are no longer used. ........ r62424 | mark.dickinson | 2008-04-20 23:39:04 +0200 (Sun, 20 Apr 2008) | 4 lines math.atan2 is misbehaving on Windows; this patch should fix the problem in the same way that the cmath.phase problems were fixed. ........
Diffstat (limited to 'Modules')
-rw-r--r--Modules/cmathmodule.c11
-rw-r--r--Modules/mathmodule.c38
2 files changed, 47 insertions, 2 deletions
diff --git a/Modules/cmathmodule.c b/Modules/cmathmodule.c
index 347f88d..d6d1f27 100644
--- a/Modules/cmathmodule.c
+++ b/Modules/cmathmodule.c
@@ -264,7 +264,8 @@ c_atan(Py_complex z)
return r;
}
-/* Windows screws up atan2 for inf and nan */
+/* Windows screws up atan2 for inf and nan, and alpha Tru64 5.1 doesn't follow
+ C99 for atan2(0., 0.). */
static double
c_atan2(Py_complex z)
{
@@ -282,6 +283,14 @@ c_atan2(Py_complex z)
/* atan2(+-inf, x) == +-pi/2 for finite x */
return copysign(0.5*Py_MATH_PI, z.imag);
}
+ if (Py_IS_INFINITY(z.real) || z.imag == 0.) {
+ if (copysign(1., z.real) == 1.)
+ /* atan2(+-y, +inf) = atan2(+-0, +x) = +-0. */
+ return copysign(0., z.imag);
+ else
+ /* atan2(+-y, -inf) = atan2(+-0., -x) = +-pi. */
+ return copysign(Py_MATH_PI, z.imag);
+ }
return atan2(z.imag, z.real);
}
diff --git a/Modules/mathmodule.c b/Modules/mathmodule.c
index 19ed1b1..3cf1133 100644
--- a/Modules/mathmodule.c
+++ b/Modules/mathmodule.c
@@ -96,6 +96,42 @@ is_error(double x)
}
/*
+ wrapper for atan2 that deals directly with special cases before
+ delegating to the platform libm for the remaining cases. This
+ is necessary to get consistent behaviour across platforms.
+ Windows, FreeBSD and alpha Tru64 are amongst platforms that don't
+ always follow C99.
+*/
+
+static double
+m_atan2(double y, double x)
+{
+ if (Py_IS_NAN(x) || Py_IS_NAN(y))
+ return Py_NAN;
+ if (Py_IS_INFINITY(y)) {
+ if (Py_IS_INFINITY(x)) {
+ if (copysign(1., x) == 1.)
+ /* atan2(+-inf, +inf) == +-pi/4 */
+ return copysign(0.25*Py_MATH_PI, y);
+ else
+ /* atan2(+-inf, -inf) == +-pi*3/4 */
+ return copysign(0.75*Py_MATH_PI, y);
+ }
+ /* atan2(+-inf, x) == +-pi/2 for finite x */
+ return copysign(0.5*Py_MATH_PI, y);
+ }
+ if (Py_IS_INFINITY(x) || y == 0.) {
+ if (copysign(1., x) == 1.)
+ /* atan2(+-y, +inf) = atan2(+-0, +x) = +-0. */
+ return copysign(0., y);
+ else
+ /* atan2(+-y, -inf) = atan2(+-0., -x) = +-pi. */
+ return copysign(Py_MATH_PI, y);
+ }
+ return atan2(y, x);
+}
+
+/*
math_1 is used to wrap a libm function f that takes a double
arguments and returns a double.
@@ -250,7 +286,7 @@ FUNC1(asinh, asinh, 0,
"asinh(x)\n\nReturn the hyperbolic arc sine (measured in radians) of x.")
FUNC1(atan, atan, 0,
"atan(x)\n\nReturn the arc tangent (measured in radians) of x.")
-FUNC2(atan2, atan2,
+FUNC2(atan2, m_atan2,
"atan2(y, x)\n\nReturn the arc tangent (measured in radians) of y/x.\n"
"Unlike atan(y/x), the signs of both x and y are considered.")
FUNC1(atanh, atanh, 0,