On Tue, Jul 7, 2015 at 3:52 PM, Bikash Kanungo <[email protected]> wrote:
> Hi Matthew, > > I couldn't follow your reply. It seems a bit unrelated to my query. > Your matrix actually looks like M = A + v^T v, where A is sparse and v is a small collection of vectors. It is better is you handle it this way than putting a dense row into a traditional sparse matrix. Matt > > Thanks, > Bikash > > On Tue, Jul 7, 2015 at 4:42 PM, Matthew Knepley <[email protected]> wrote: > >> On Tue, Jul 7, 2015 at 3:36 PM, Bikash Kanungo <[email protected]> wrote: >> >>> Hi Matthew, >>> >>> The entries to the last few rows of my matrix has non-local >>> contributions from a large number of processors. Since the matrix is >>> symmetric, I need not set the non-local entries in the last few rows as >>> they are equal to their transpose entries, which on the other hand are >>> stored as local entries in their respective processors. >>> >> >> This is really a sparse matrix with a low rank update. It is much easier >> to handle it this way. There are explicit formulae for the inverse >> in terms of the inverse of the two parts (Sherman-Morrison-Woodbury), and >> other operations can be similarly simplified. We might not >> have all the support now, but pressing forward on this front is likely to >> be much more fruitful. >> >> Thanks, >> >> Matt >> >> >>> Thanks, >>> Bikash >>> >>> On Tue, Jul 7, 2015 at 4:25 PM, Matthew Knepley <[email protected]> >>> wrote: >>> >>>> On Tue, Jul 7, 2015 at 3:22 PM, Bikash Kanungo <[email protected]> >>>> wrote: >>>> >>>>> Hi, >>>>> >>>>> Is there a way to ignore the lower (or upper) triangular entries in an >>>>> MATMPIAIJ matrix when I know my matrix is symmetric? I can see a >>>>> MAT_SYMMETRIC option in MatSetOption, but I don't think it ignores any >>>>> lower (or upper) triangular entry. >>>>> >>>> >>>> Why do you want this? >>>> >>>> >>>>> I cannot use MATMPISBAIJ due to MatMatMult incompatibility with >>>>> MATMPIAIJ. >>>>> >>>> >>>> This is the only way. MatMatMult() is quite complex and there is no >>>> real advantage to ignoring >>>> the entries, so we have not implemented it here. >>>> >>>> Matt >>>> >>>> >>>>> Thanks, >>>>> Bikash >>>>> >>>>> -- >>>>> Bikash S. Kanungo >>>>> PhD Student >>>>> Computational Materials Physics Group >>>>> Mechanical Engineering >>>>> University of Michigan >>>>> >>>>> >>>> >>>> >>>> -- >>>> 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 >>>> >>> >>> >>> >>> -- >>> Bikash S. Kanungo >>> PhD Student >>> Computational Materials Physics Group >>> Mechanical Engineering >>> University of Michigan >>> >>> >> >> >> -- >> 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 >> > > > > -- > Bikash S. Kanungo > PhD Student > Computational Materials Physics Group > Mechanical Engineering > University of Michigan > > -- 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
