Does your matrix come from an unstructured grid? If so, then you'll need to use
a partitioning package such as permits. Read section 3.5 of the manual
http://www.mcs.anl.gov/petsc/petsc-current/docs/manual.pdf and also see the
example
http://www.mcs.anl.gov/petsc/petsc-current/src/mat/examples/tutorials/ex15.c.html
----- Original Message -----
> I want to load a sparse matrix from a file (in PETSc binary format).
> The matrix will be in MPIAIJ format.
> I want it is a balanced load: each processor will have nearly equal
> number of nonzeros.
> I don't come up with a sequence of PETSc calls to do that.
> On Sat, Jan 14, 2012 at 11:41 AM, Jed Brown < jedbrown at mcs.anl.gov >
> wrote:
> > On Sat, Jan 14, 2012 at 12:38, Junchao Zhang <
> > junchao.zhang at gmail.com
> > > wrote:
> > > Does PETSc provide convenient functions to compute this layout(
> > > i.e.,#
> > > rows on each processor), or I have to do it myself?
> > > I browsed PETSc document and did not find them.
> > MatSetSizes() lets you specify local and/or global sizes. If you
> > specify both, it checks that they are compatible. The implementation
> > uses
> > http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Sys/PetscSplitOwnership.html
> > If these are not suitable for your purposes, can you be more
> > specific
> > about what you would like to do?
> --
> Junchao Zhang
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