[petsc-users] Advice Being Sought

[David Scott]

Hello Barry,

On 23/04/2013 02:36, Barry Smith wrote:
>    David,
>
>      We would be very interested in determining what is "going wrong" with the solver here since we hope to make it robust.  Would it be possible for you to use a MatView() and VecView() on the matrix and the right hand side with a binary viewer when it "goes bad" and send us the resulting file?
>
>     Barry
>
> We'd run the gamg solver on your matrix and track down what is happening.
>
>

I shall try to do what you ask but I shall try to do it for a smaller 
domain (2 million rather than 11 million points) than I have been 
working on recently.

I am uncertain what I should do precisely. With reference to the code 
that I attached to a previous message should I insert something like
   PetscViewer viewer
   call MatView(B, viewer, ierr)
   call PetscViewerBinaryOpen(PETSC_COMM_WORLD, 'BinaryMatrix',  &
     FILE_MODE_WRITE, viewer, ierr)
   call PetscViewerDestroy(viewer, ierr)
in compute_matrix after B has been assembled (and similar code in 
compute_rhs).

David
-- 
Dr. D. M. Scott
Applications Consultant
Edinburgh Parallel Computing Centre
Tel. 0131 650 5921

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