Re: Parallel ISCreateGeneral()

[Tim Stitt <timothy.stitt@xxxxxxxx>]

Oh...ok I am now officially confused.

I have developed a serial code for getting the first k rows of an 
inverted sparse matrix..thanks to PETSC users/developers help this past 
week.

In that code I was calling MatLUFactorSymbolic() and 
MatLUFactorNumeric() to factor the sparse matrix and then calling 
MatSolve for each of the first k columns in the identity matrix as the 
RHS. I then varied the matrix type from the command line to test MUMPS, 
SUPERLU etc. for the best performance.

Now I just want to translate the code into a parallel version...so I now 
assemble rows in a distributed fashion and now working on translating 
the MatLUFactorSymbolic() and MatLUFactorNumeric() calls which require 
index sets...hence my original question.

Are you saying that I now shouldn't be calling those routines?

Tim.

Matthew Knepley wrote:
> On Nov 18, 2007 11:52 AM, Tim Stitt <timothy.stitt@xxxxxxxx> wrote:
>   
> > 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?
> >     
>
> To be consistent, these would be local sizes and global numberings. However,
> I am not sure why you would be doing this. I do not believe any of the parallel
> LU packages accept an ordering from the user (they calculate their own),
> and I would really only use them from a KSP (or PC at the least).
>
>   Matt
>
>   
> > 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)
> >
> >
> >     
>
>
>
>   


--
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)