[petsc-users] Nonzero I-j locations

[Smith, Barry F.]

  Manav,

  For parallel sparse matrices using the standard PETSc formats the matrix is stored in two parts on each process (see the details in MatCreateAIJ()) thus there is no inexpensive way to access directly the IJ locations as a single local matrix. What are you hoping to use the information for? Perhaps we have other suggestions on how to achieve the goal.

   Barry


> On May 29, 2019, at 2:27 PM, Manav Bhatia via petsc-users <petsc-users at mcs.anl.gov> wrote:
> 
> Hi, 
> 
>    Once a MPI-AIJ matrix has been assembled, is there a method to get the nonzero I-J locations? I see one for sequential matrices here: https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatGetRowIJ.html , but not for parallel matrices. 
> 
> Regards,
> Manav
> 
>