[Trilinos-Users] How to import non-local CSR matrix elements?

[Williams, Alan B]

Riccardo,

Unfortunately Epetra_FECrsMatrix only supports assembly of non-local data but not retrieval of non-local data afterwards.

But you can do an import operation on matrices that is the same as what you've done for vectors.

Alan


> -----Original Message-----
> From: trilinos-users-bounces at software.sandia.gov [mailto:trilinos-
> users-bounces at software.sandia.gov] On Behalf Of rrossi at cimne.upc.edu
> Sent: Wednesday, January 05, 2011 4:49 PM
> To: trilinos-users at software.sandia.gov
> Subject: [Trilinos-Users] How to import non-local CSR matrix elements?
> 
> Dear list,
> 
>  i am dealing with a somewhat non standard problem: i assembled an
> Epetra_FECrsMatrix, and i would need
> 
> to get a copy of the values stored in the matrix. To explain better,
> suppose that i have the matrix
> 
> 2 3 * *
> 
> 4 5 6 *
> 
> * * 1 *
> 
> * * 2 1
> 
> where the processor 1 owns the first two lines and the processor 2 owns
> the second ones
> 
> i would like to be able (as process 2) to query for the values that
> correspond to a given set of indices, which are however owned by
> processor
> 1,
> 
> say
> 
> (1,1)
> 
> (2,1)
> 
> from having a look to the documentation i found that the most similar
> thing appears to be the function
> 
> int 	ExtractGlobalRowCopy [1] (int GlobalRow, int Length, int
> 
> however this is only defined for CRSMAtrix and does not allow accessing
> to non local data.
> 
> For  Epetra_FEVector i am currently doing the following to get a copy
> of
> both local and non local data:
>   		 //defining the importer class
> 
>   		 Epetra_Import importer( dof_update_map, Dx.Map() );
> 
>   		 //defining a temporary vector to gather all of the values
> needed
> 
>   		 Epetra_Vector temp( importer.TargetMap() );
> 
>   		 //importing in the new temp vector the values
> 
>   		 int ierr = temp.Import(Dx,importer,Insert);
> 
>   		 if(ierr != 0) KRATOS_ERROR(std::logic_error,"Epetra
> failure
> found","");
> 
> 
> Is it possible to do something similar for my problem?
> Any help/pointer to the correct documentation would be very welcome
> 
> thank you all in advance
> Riccardo
> 
> 
> 
> 
> 
> _______________________________________________
> Trilinos-Users mailing list
> Trilinos-Users at software.sandia.gov
> http://software.sandia.gov/mailman/listinfo/trilinos-users