[petsc-users] Problem with Mat.setpreallocationNNZ in petsc4py

[Matthew Knepley]

On Sat, Jul 7, 2012 at 10:58 AM, Xin Zhao <sean.null at gmail.com> wrote:

> Dear all,
>
> I generate a matrix L by
> DA =PETSc.DA().create(...some...)
> L = DA.create()
>

Is this createMatrix()? The matrix returned from a DA is already
preallocated.

   Matt


> Then I want to preallocate memory for L
> L.setPreallocationNNZ((3,2))
> This works when for mpiexec -np 1
> but it gives the error message below when mpiexec -np 4
>
> [3] MatAnyAIJSetPreallocation() line 311 in
> petsc4py-1.2/src/include/custom.h
> [3] Operation done in wrong order
> [3] matrix is already preallocated
>
> How to solve this?
>
> Thanks in advance.
>
> Cheers,
> Xin
>



-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener
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