[SciPy-User] ANN: SciPy 0.11.0 release candidate 2

Pauli Virtanen pav@iki...
Tue Aug 14 06:21:52 CDT 2012

Ralf Gommers <ralf.gommers <at> gmail.com> writes:
> Does anyone have an idea about that test_singular failure?

That's very likely some problem with the underlying LAPACK library.
I think the problem solved is close to a numerical instability.

The failing comparison compares eigenvalues computed by

    eig(A, B)
    eig(A, B, left=False, right=False)

which differ solely in passing 'N' vs. 'V' to DGGEV. The eigenvalue
property of the former is also checked and seems to pass. Interestingly,
the result obtained from the two seems to differ (therefore, the latter
is probably wrong), which appears to point to a LAPACK issue.

Here, it would be interesting to know if the problem occurs with
the official Scipy binaries, or something else.

Pauli Virtanen

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