[petsc-users] Mixed sparse and dense CG

[Ross Brodie]

Jed

Thanks i will pursue it through MATELEMENTAL.

Ross

> On 12 Dec 2013, at 18:21, Jed Brown <jedbrown at mcs.anl.gov> wrote:
> 
> Ross Brodie <ross.c.brodie at icloud.com> writes:
> 
>> I have considered using libElemental for the dense part (to make use
>> of the grid cyclic layout) and PETSc for the sparse part of the PCG
>> matvec product but I am not sure it is wise to mix packages.
> 
> The PETSc interface to Elemental can do this.  In principle, you don't
> have to deal with the cyclic ordering, but you should assemble the rows
> and columns returned by MatGetOwnershipIS().
> 
>> On a different note could you clarify the terminology for the
>> sequential vector VECSEQ. Does it mean: (i) It is an independent
>> uniprocessor object such that the data storage is not distributed and
>> if you change an element on one process the change is NOT reflected on
>> other processes,
> 
> Yes, and only makes sense on a communicator of size 1 (effectively
> PETSC_COMM_SELF).