[Trilinos-Users] Epetra, Isorropia (Zoltan) - 2D matrix partition

[Erik Boman]

Gyorgy,

I suppose by "2D partitioning" you refer to the partitioning of the 
nonzeros within a matrix? In that case, rows are actually split among 
processes and this breaks some packages in Trilinos. The short answer is 
that Isorropia does not currently support 1D-to-2D rebalancing (but it 
is something we are considering for the future). However, Epetra works 
with matrices distributed in 2D fashion, in particular, matvecs work 
well. Unfortunately, most preconditioners do not support this.

I am curious what your application is and why you think 2D would be 
better (more scalable) than 1D distribution.

Thanks,
Erik

PS: Partitioning of matrix rows based on 2D geometry is a completely 
different meaning of "2D partitioning".

Gyorgy Matyasfalvi wrote:
> Dear Users:
> I was wondering if it is possible to create a 2D partitioned Epetra 
> sparse matrix and then feed that to Isorropia for rebalancing?
> To me it seems that all the Epetra sparse matrices are 1D row 
> partitioned. But the matrix I'm dealing with is too big for 1D 
> partitioning to be enough.
> Thanks for the help!
> Best,
> Gyorgy 
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