The description matches MATNEST (MATCOMPOSITE is for a sum or product of matrices) or parallel decompositions. Also consider the assembly style of src/snes/tutorials/ex28.c, which can create either a monolithic or block (MATNEST) matrix without extra storage or conversion costs.
Mark Adams <mfad...@lbl.gov> writes: > Do you know what kind of solver works well for this problem? > > You probably want to figure that out first and not worry about efficiency. > > MATCOMPOSITE does what you want but not all solvers will work with it. > > Where does this problem come from? We have a lot of experience and might > know something. > > Mark > > On Mon, Dec 12, 2022 at 1:33 PM Peder Jørgensgaard Olesen via petsc-users < > petsc-users@mcs.anl.gov> wrote: > >> Hello >> >> >> I have a set of sparse matrices (A1, A2, ...) , and need to generate a >> larger matrix B with these as submatrices. I do not know the precise sparse >> layouts of the A's (only that each row has one or two non-zero values), >> and extracting *all* values to copy into B seems incredibly wasteful. How >> can I make use of the sparsity to solve this efficiently? >> >> >> Thanks, >> >> Peder >> >> >> >> Peder Jørgensgaard Olesen >> PhD student >> Department of Civil and Mechanical Engineering >> >> pj...@mek.dtu.dk >> Koppels Allé >> Building 403, room 105 >> 2800 Kgs. Lyngby >> www.dtu.dk/english >> >>
