[petsc-users] Function of MatMPIAIJGetSeqAIJ

[Smith, Barry F.]

> On Sep 13, 2018, at 12:46 PM, Ian Lin <iancclin at umich.edu> wrote:
> 
> Hi,
> 
> I am thinking of using MatMPIAIJGetSeqAIJ to have a reference to the local SeqAIJ Matrix (without actually creating a new matrix). Since I don’t see any description of that function on petsc website, I want to confirm if this functions works similar to MatDenseGetLocalMatrix.

   It returns the two SeqAIJ matrices that make up the on-process part of the the parallel MPIAIJ matrix so in that sense is like MatDenseGetLocalMatrix.
See MatCreateMPIAIJ for the exact meaning of these two matrices; the final argument maps from the columns of the "off-diagonal" matrix Ao to the global numbering of the original MPIAIJ matrix.

   Barry

> 
> Many thanks,
> Ian