> On May 19, 2015, at 5:47 PM, Fande Kong <[email protected]> wrote: > > If I am interested in extracting some remote and local rows and columns but > as another sequential matrix, then I have to use MatGetSubMatrices?
Yes > There are no ways to use MatGetSubMatrix to get a sequential matrix? No > Because I am only interested in one sequential matrix per core not multi > matrices. You can just ask for one matrix with MatGetSubMatrices() will give you one sequential matrix per MPI process. > > Fande, > > On Tue, May 19, 2015 at 4:40 PM, Barry Smith <[email protected]> wrote: > > > On May 19, 2015, at 5:33 PM, Fande Kong <[email protected]> wrote: > > > > Hi all, > > > > I am confused with MatGetSubMatrix and MatGetSubMatrices. In my > > understanding, I think MatGetSubMatrix extracts local rows and columns to > > form another parallel matrix with the same communicator, while > > MatGetSubMatrices extracts both local and remote entities to construct some > > sequential matrices. Is it right? > > Yes except that MatGetSubMatrix can also use remote rows (and columns) for > the part that is on a particular processor. That is it is not restricted to > only grabbing local rows/columns in the new parallel matrix. > > > > > > Thanks, > > > > Fande, > >
