Hi Matthew, I couldn't follow your reply. It seems a bit unrelated to my query.
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
