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Re: Parallel ISCreateGeneral()

Matt,

It is in setup for MatLUFactorSymbolic() and MatLUFactorNumeric() calls which require index sets. I have distributed my rows across the processes and now just a bit confused about the arguments to the ISCreateGeneral() routine to set up the IS sets used by the Factor routines in parallel.

So my basic question is what in general is the length and integers that get passed to ISCreateGeneral() when doing this type of calculation in parallel? Are they local index values (0..#rows on process-1) or do they refer to the distributed indices of the global matrix?

Tim.

Matthew Knepley wrote:
On Nov 18, 2007 11:34 AM, Tim Stitt <timothy.stitt@xxxxxxxx> wrote:
OK..so I should be using the aggregate length returned by
MatGetOwnershipRange() routine?

If you are using it to permute a Mat, yes.

  Matt

Thanks Matt for you help.


Matthew Knepley wrote:
IS are not really parallel, so all the lengths, etc. only refer to local things.

  Matt

On Nov 18, 2007 11:22 AM, Tim Stitt <timothy.stitt@xxxxxxxx> wrote:

Hi all,

Just wanted to know if the "the length of the index set" for a call to
ISCreateGeneral() in a parallel code, is a global length, or the length
of the local elements on each process?

Thanks,

Tim.

--
Dr. Timothy Stitt <timothy_dot_stitt_at_ichec.ie>
HPC Application Consultant - ICHEC (www.ichec.ie)

Dublin Institute for Advanced Studies
5 Merrion Square - Dublin 2 - Ireland

+353-1-6621333 (tel) / +353-1-6621477 (fax)





--
Dr. Timothy Stitt <timothy_dot_stitt_at_ichec.ie>
HPC Application Consultant - ICHEC (www.ichec.ie)

Dublin Institute for Advanced Studies
5 Merrion Square - Dublin 2 - Ireland

+353-1-6621333 (tel) / +353-1-6621477 (fax)







--
Dr. Timothy Stitt <timothy_dot_stitt_at_ichec.ie>
HPC Application Consultant - ICHEC (www.ichec.ie)

Dublin Institute for Advanced Studies
5 Merrion Square - Dublin 2 - Ireland

+353-1-6621333 (tel) / +353-1-6621477 (fax)