[Trilinos-Users] Error in AZ_extract_comm_info

Heroux, Michael A maherou at sandia.gov
Thu Sep 17 21:55:51 MDT 2009


AztecOO constrains the column map of the matrix such that column IDs associated with rows on other processors must be ordered after columns IDs that match row IDs on the same processor.  Epetra will automatically organize the column map this way if allowed to do so.  Are you some how specifying the column map?  I don't see this happening in your code, so maybe there is something going on with your matrix.

If you want to put your matrix somewhere for me to fetch, please do so, and send your test code.  I can look at it.


On 9/17/09 4:16 PM, "Dorian Krause" <dorian.krause at lu.unisi.ch> wrote:

Hi again,

I was able to reproduce this problem using the ex1.cpp from the aztecoo
examples and just replacing the construction of the Laplace stiffness
matrix by a read from a file using EpetraExt::MatrixMarketFileToCrsMatrix.
Are there any constraints on the input matrices to AztecOO? I could send
the test example (its ~ 3 MB so I think it's not a good idea to attach
it to this mail) if someone is interested ...

I'm sorry if this problem has already been discussed elsewhere: I tried
to search the trilinos-user archive but couldn't get beyound the
password pop-up.


Dorian Krause wrote:
> Hi,
> using AztecOO to solve a distributed system, gives me the error
> AZ_extract_comm_info: Received elements must be stored after
>                    all 1107 local elements
> My code looks as follows:
> ========================================
> map  = new Epetra_Map(-1, nrows, 0, *communicator);
> vecX = new Epetra_Vector(*map);
> vecB = new Epetra_Vector(*map);
> mat  = new Epetra_CrsMatrix(Copy,*map, /* maximal bandwith */);
> /* Insert into matrix */
> problem = new Epetra_LinearProblem(mat, vecX, vecB);
> solver  = new AztecOO(*problem);
> solver->SetAztecOption( AZ_solver, AZ_cg);
> solver->SetAztecOption( AZ_precond, AZ_Jacobi);
> /* initialize vecX and vecB */
> solver->Iterate(maxiter,TOL);
> ========================================
> If I understand it correctly the matrix mat created with this code is
> distributed rowwise on the vectors, right?
> Where might this error come from? I checked that all indices are in
> range but I don't know what else I should look at ...
> Many thanks in advance,
> Dorian
> _______________________________________________
> Trilinos-Users mailing list
> Trilinos-Users at software.sandia.gov
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