about ISCreateGeneral() and MatGetSubMatrices()

[Matthew Knepley]

On Mon, Sep 29, 2008 at 1:53 PM, Yujie <recrusader at gmail.com> wrote:
> that is, even if one use MPI_COMM to create an IS object. it is always a
> sequential object, right? thanks, Matt.

It has some collective operations, just not the one you were asking for.

  Matt

> On Mon, Sep 29, 2008 at 11:40 AM, Matthew Knepley <knepley at gmail.com> wrote:
>>
>> 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
>>
>
>



-- 
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