about ISCreateGeneral() and MatGetSubMatrices()

[Matthew Knepley]

On Mon, Sep 29, 2008 at 1:33 PM, Yujie <recrusader at gmail.com> wrote:
> I am wondering how to use ISCreateGeneral().
>
> Assuming I use 2cpus when I run my codes. I use MPI_COMM to create an object
> of IS using ISCreateGeneral() and an array on a single cpu. how to
> distribute this IS object on these 2cpus? If I use MatGetSubMatrices() to
> get different submatrices on different cpus. I am wondering how to create IS
> object, using PETSC_COMM_SELF? thanks a lot.

You provide the indices you want for each process \emph{locally} on
that process.
There is no facility for communicating indices in IS.

  Matt

> Regards,
>
> Yujie
-- 
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