[SciPy-Dev] segfault in test_qhull.TestRidgeIter2D.test_complicated

Pauli Virtanen pav@iki...
Mon Nov 15 06:07:16 CST 2010

Mon, 15 Nov 2010 11:10:40 +0100, Jens Nielsen wrote:
> I get a segmentation fault at the same point on ubuntu 10.10 both 64 bit
> and 32 bit versions but only when linking against atlas. Linking
> against blas and lapack only is fine.

Ok, this bug is absent if Qhull is compiled without optimizations, and 
present if compiled with -O2.

Qhull apparently breaks gcc's strict-aliasing assumptions, and compiling 
with 'OPT="-fno-strict-aliasing -O2" python setup.py ...' makes it work 
again. This should probably be enabled by default, or one would need to 
check if the aliasing issues can be fixed on the source code level.

Pauli Virtanen

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