Waad Subber w_subber at
Tue May 20 15:16:44 CDT 2008

 Thank you Matt,

Any suggestion to solve the problem I am trying to tackle. I want to solve a linear system: 

Sum(A_i) u= Sum(f_i) , i=1.... to No. of CPUs. 

Where  A_i is a sparse sequential matrix and f_i is a sequential vector. Each CPU has one matrix and one vector of the same size. Now I want to sum up and solve the system in parallel.

Thanks again


Matthew Knepley <knepley at> wrote: On Tue, May 20, 2008 at 2:12 PM, Waad Subber  wrote:
> Hi,
> I am trying to construct a sparse parallel matrix (MPIAIJ) by adding up
> sparse sequential matrices (SeqAIJ) from each CPU. I am using
> MatMerge_SeqsToMPI(MPI_Comm comm,Mat seqmat,PetscInt m,PetscInt n,MatReuse
> scall,Mat *mpimat)
> to do that. However, when I compile the code I get the following
>  undefined reference to `matmerge_seqstompi_'
> collect2: ld returned 1 exit status
> make: *** [all] Error 1
> Am I using this function correctly ?

These have no Fortran bindings right now.


> Thanks
> Waad

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

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