[SciPy-Dev] arpack failures 64-bit

[Aric Hagberg]

On Sat, Jun 19, 2010 at 8:47 AM, Ralf Gommers
<ralf.gommers at googlemail.com> wrote:
>
>
> On Sat, Jun 19, 2010 at 10:03 PM, Aric Hagberg <aric.hagberg at gmail.com>
> wrote:
>>
>> On Fri, Jun 18, 2010 at 11:00 PM, Ralf Gommers
>> <ralf.gommers at googlemail.com> wrote:
>> > Arpack test failures have been reported by several people, all on 64
>> > bit. On
>> > 32-bit it's fine.
>> >
>> > ======================================================================
>> > ERROR: test_nonsymmetric_modes (test_arpack.TestEigenNonSymmetric)
>> > ----------------------------------------------------------------------
>> > Traceback (most recent call last):
>> >  File
>> >
>> > "/sw/lib/python2.6/site-packages/scipy/sparse/linalg/eigen/arpack/tests/test_arpack.py",
>> > line 204, in test_nonsymmetric_modes
>> >    self.eval_evec(m,typ,k,which)
>> >  File
>> >
>> > "/sw/lib/python2.6/site-packages/scipy/sparse/linalg/eigen/arpack/tests/test_arpack.py",
>> > line 186, in eval_evec
>> >    eval,evec=eigen(a,k,which=which,**kwds)
>> >  File
>> >
>> > "/sw/lib/python2.6/site-packages/scipy/sparse/linalg/eigen/arpack/arpack.py",
>> > line 397,
>> > in eigen
>> >    params.iterate()
>> >  File
>> >
>> > "/sw/lib/python2.6/site-packages/scipy/sparse/linalg/eigen/arpack/arpack.py",
>> > line 222,
>> > in iterate
>> >    raise RuntimeError("Error info=%d in arpack" % self.info)
>> > RuntimeError: Error info=-8 in arpack
>> >
>> > For the full list of errors see
>> >
>> > http://article.gmane.org/gmane.comp.python.scientific.devel/13706/match=arpack
>> > (on OS X).
>> > Similar report on Linux:
>> > http://thread.gmane.org/gmane.comp.python.scientific.devel/8551
>> > This seems also related: http://projects.scipy.org/scipy/ticket/725.
>> >
>> > Does anyone have time to look at this soon? If not, can I mark them as
>> > knownfail for 0.8.0?
>>
>> I took a quick look at this but I don't have a fix and I also can't
>> reproduce the problem on 64 bit Linux.
>>
>> The error is coming from the LAPACK routine zlahqr
>> which is what the -8 error code refers to.  See error codes at
>>
>> http://projects.scipy.org/scipy/browser/trunk/scipy/sparse/linalg/eigen/arpack/ARPACK/SRC/zneupd.f#L149
>> :
>>
>> c          = -8: Error return from LAPACK eigenvalue calculation.
>> c                This should never happened.
>>
>> (and around line 557 where the error is generated after calling zlahqr)
>> and the section the
>>
>> http://projects.scipy.org/scipy/browser/trunk/scipy/sparse/linalg/eigen/arpack/ARPACK/SRC/zneupd.f#L557
>>
>> The LAPACK subroutine zlahqr in currently included in scipy since in
>> earlier
>> testing (on Linux) we found that this function as included in the
>> packaged libraries was producing errors.
>>
>> Further, the interface to complex number functions had to be hacked
>> to make it work on OSX since the OSX distributed LAPACK had a different
>> (C, rather than Fortran) interface:
>> http://projects.scipy.org/scipy/ticket/725
>>
>> Is this an OSX issue only? Those tests pass for me on 64 bit Linux.
>> Perhaps we need to revisit the code David inserted (see ticket 725 above)?
>
> Yes, looks like it is OS X (10.6) only. This report:
> http://article.gmane.org/gmane.comp.python.scientific.devel/13705/match=test_arpack+testeigennonsymmetric
> seems to claim that these tests did not fail for 0.7.2.
>

I have access to a OSX 10.6 machine but no 64 bit python devel
environment there.   If someone who does can help me debug this
(or tell me the best/fast way to set up the 64 bit tools) I can
make a  little time in the next couple days to try to fix it.

Aric