[SciPy-dev] new sparsetools + umfpack

Nils Wagner nwagner at iam.uni-stuttgart.de
Wed Jan 10 06:46:33 CST 2007


Robert Cimrman wrote:
> New sparsetools implementation does not require CSR/CSC column/row
> indices to be sorted in ascending order, while UMFPACK does. Currently,
> every call to umfpack module (e.g. via linsolve.solve) implicitly calls
> ensure_sorted_indices(inplace=True) method of CSR/CSC matrix, which is
> rather fast, but in many cases is not necessary and the overhead can
> become significant when solving lots of linear systems (e.g.
> FE-discretized evolutionary nonlinear PDEs) - in this case, only one
> call to ensure_sorted_indices() is necessary, then only values change,
> not the structure.
>
> Therefore, if there are no objections, I would like to remove the
> implicit call to ensure_sorted_indices() from umfpack and require user
> to call it explicitly (only if necessary) - an exception will be raised
> by umfpack if the matrix is not in correct form, so it cannot lead to
> hidden bugs. I will document this in linsolve, of course.
>
> r.
>
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>   
Just curious. Is the umfpack directory in the sandbox obsolete ?

Nils
 


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