[SciPy-User] many test failures on windows 64

[Charles R Harris]

On Tue, Jul 6, 2010 at 1:20 PM, Robin <robince at gmail.com> wrote:

> On Tue, Jul 6, 2010 at 7:43 PM, Pauli Virtanen <pav at iki.fi> wrote:
> > Tue, 06 Jul 2010 11:53:22 -0600, Charles R Harris wrote:
> > [clip]
> >> Let's get this thread back to the errors. The problems seem specific to
> >> the python.org amd64 python, is that correct?
> >
> > The SuperLU failures puzzle me. It should be "straightforward" C code,
> > and I don't understand what can go wrong there. The "Factor is exactly
> > singular" error indicates essentially means that SuperLU thinks it
> > detects a zero pivot or something, so something seems to fail at a fairly
> > low level.
> >
> > This seems quite difficult to debug without a Win-64 at hand.
> >
> > Another thing is that Gohlke's binaries are also built against MKL, and
> > SuperLU does call BLAS routines. I wonder if something can break because
> > of that...
> >
> > @Robin: Also, for the cases where a wrong result is produced with no
> > error: is it easy to write a small test program demonstrating this? If
> > yes, could you write one?
>
> Yes, below is a simple example. On my mac it works:
> In [10]: run -i sptest.py
> [-0.34841705 -0.23272338  0.27248558]
> [-0.34841705 -0.23272338  0.27248558]
>
> On the 64bit windows installation:
> In [7]: run -i spsolve_test.py
> [ 0.08507826  1.04401349 -1.56609783]
> [-0.52208434 -1.48101957 -1.56609783]
> In [8]: run -i spsolve_test.py
> [ 0.71923676 -0.12209489 -0.16069061]
> [-0.2827855   0.55854616 -0.16069061]
>
> import numpy as np
> import scipy as sp
> import scipy.sparse.linalg
>
> Adense = np.matrix([[ 0.,  1.,  1.],
>        [ 1.,  0.,  1.],
>        [ 0.,  0.,  1.]])
> As =  sp.sparse.csc_matrix(Adense)
> x = np.random.randn(3)
> b = As.matvec(x)
>
> print x
> print sp.sparse.linalg.spsolve(As, b)
>

Is x the same on both machines?

Chuck
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