[Scipy-tickets] [SciPy] #231: A wrapper for ARPACK
SciPy
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Tue Oct 10 10:58:40 CDT 2006
#231: A wrapper for ARPACK
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Reporter: nils | Owner: somebody
Type: enhancement | Status: new
Priority: normal | Milestone:
Component: scipy.sparse | Version:
Severity: normal | Resolution:
Keywords: |
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Comment (by NeilenMarais):
Hi.
I've also tried wrapping ARPACK with similar results. I actually only
tried wrapping the general (i.e. non-symmetric) matrix routines. I
narrowed the problem down the call to the post-proccessing <s,d>neupd
routine. If eigenvectors aren't requested, it does calculate the correct
eigenvalues reliably. If eigenvectors are requested, repeated runs will
eventually turn up the correct results.
I have tried all sorts of things (super-sizing some of the workspaces) to
no avail. I wonder if the problems are caused by a bug in F2PY, or I guess
some subtle ARPACK bug that isn't aparent if there is no python+scipy also
in the process. I'm interested to hear that the symmetric and complex
routines work properly.
I have also gotten the shift-invert mode working, again without
calculating eigenvectors, since I'm solving the generalised eigensystem
produced by my FEM code. By combining it with linsolve.splu() I can solve
fair sized problems fairly quickly. Using instead the unpreconditioned
iterative solvers seems to run a very very long time... But at least I can
solve large problems without killing my system :) Actually I don't know if
it works properly yet, since I'm still waiting.
--
Ticket URL: <http://projects.scipy.org/scipy/scipy/ticket/231#comment:2>
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