[petsc-users] From AIJ to CSR

[Barry Smith]

On Jul 23, 2013, at 9:09 PM, Su Yan <suyan0 at gmail.com> wrote:

> Thanks, Barry. 
> 
> The reason I need to access these structures is that I am trying to interface PETSc with MKL through the PCSHELL interface. I need the access to the basic CSR structure in order to invoke the ILUT subroutine in the MKL package. 

   Ok

> 
> BTW, should it be MatGetRowIJ() instead of MatGetIJ() ?

   Yes, sorry.

   Barry

> 
> Thanks,
> Su
> 
> 
> 
> On Tue, Jul 23, 2013 at 9:03 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
> 
> On Jul 23, 2013, at 8:59 PM, Su Yan <suyan0 at gmail.com> wrote:
> 
> > Hi, is there any way that I can extract the index information and element array from a AIJ matrix? Say, I have a Mat A, which is created using the CSR format with MatCreateSeqAIJ(). How can I get int *ia, int *ja, and double *array out of A?
> 
>    MatSeqAIJGetArray() for array and MatGetIJ() for ia and ja but we hope that generally users will never need to get access to these low-level underlying structures. Perhaps if you tell us why you want them we may suggest alternatives.
> 
>     Barry
> 
> >
> > Thanks,
> > Su
> 
>