On Wed, Jul 30, 2014 at 3:30 PM, Qin Lu <[email protected]> wrote:
> In the context of domain decompostion, if the unknowns are ordered (to > reduce the number of infills, for instance) in the way that each subdomain > may not own consecutive unknown index, does this mean the partition of the > domain will be different from the partition of the matrix? > > For example, if subdomain 1 (assigned to process 1) owns unknowns 1 and 3 > (associated with equation 1 and 3), subdomain 2 (assigned to process 2) > owns unknowns 2 and 4 (associated with equation 2 and 4) , how can I make > each process own consecutive rows? > You renumber the rows once they are partitioned. Matt > Thanks, > Qin > > *From:* Barry Smith <[email protected]> > *To:* Qin Lu <[email protected]> > *Cc:* petsc-users <[email protected]> > *Sent:* Wednesday, July 30, 2014 2:49 PM > *Subject:* Re: [petsc-users] Partition of parallel AIJ sparce matrix > > > On Jul 30, 2014, at 11:08 AM, Qin Lu <[email protected]> wrote: > > > Hello, > > > > Does a process have to own consecutive rows of the matrix? For example, > suppose the global AIJ is 4x4, partitioned by 2 processes. Does process 1 > have to own rows 1 and 2, process 2 own rows 3 and 4? > > Yes > > > Or process1 may own rows 1 and 3, and process 2 own row 2 and 4? > > However, the numbering of degrees of freedom is arbitrary. Just renumber > you degrees of freedom so the first set is on process 0, the next on > process 1 etc. > > Barry > > > > > > Thanks a lot for your help! > > > > Regards, > > Qin > > > -- 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
