Author dmalcolm
Recipients dmalcolm
Date 2011-12-05.23:24:20
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On ppc64, on this box, with glibc-2.14.90-19.ppc64, test_cmath fails with:

FAIL: test_specific_values (test.test_cmath.CMathTests)
Traceback (most recent call last):
  File "/builddir/build/BUILD/Python-2.7.2/Lib/test/", line 352,
in test_specific_values
  File "/builddir/build/BUILD/Python-2.7.2/Lib/test/", line 112,
in rAssertAlmostEqual
    '{!r} and {!r} are not sufficiently close'.format(a, b))
AssertionError: acos0200: acos(complex(1.620686051868302e+308,
Expected: complex(0.5665082609382622, -710.5420687424156)
Received: complex(0.5665082609382622, -inf)
Received value insufficiently close to expected value.

It turns out (after much debugging) that libm in this version of glibc has an architecture-specific implementation of hypot(3) which returns inf in many of the test cases in tests/cmath_testcases.txt, when the non-architecture-specific implementation returns large finite values.

See downstream bug in Fedora's bug tracker:
for more details.

Seen with the Python 2.7.2 tarball, but the code doesn't appear to have changed in hg in either the default or the 2.7 branches.

I will also file a bug in glibc's bug tracker about this.
Date User Action Args
2011-12-05 23:24:21dmalcolmsetrecipients: + dmalcolm
2011-12-05 23:24:21dmalcolmsetmessageid: <>
2011-12-05 23:24:20dmalcolmlinkissue13534 messages
2011-12-05 23:24:20dmalcolmcreate