On Thu, Jun 16, 2022 at 11:31 AM Cotter, Colin J <colin.cotter@imperial.ac.uk> wrote:
Hi folks, 
  I'm doing some stuff with ASMVankaPC applied to an extruded mesh (so I'm working on a patch of columns) and a mixed system, so the matrices are getting relatively big. Does anyone have any tips on how to use different algorithms with the solver to use less memory?
One idea I had is that I think that it would be possible to eliminate down to one single variable, solve that and back substitute. It looks like MUMPS has some Schur complement options, for example, but I don't know how to pipe the DOFs I want to eliminate down to MUMPS - is it possible?

Maybe you could write out how this saves memory? I cannot see it off the bat. It looks to me like any direct method will end up storing the equivalent of each patch matrix. If you want to save memory, you could make them on the fly, or solve them iteratively.

  Thanks,

     Matt
 
all the best
--cjc

Professor Colin Cotter (he/him)
Department of Mathematics
755, Huxley Building
Imperial College London
South Kensington Campus
United Kingdom of Great Britain and Northern Ireland
+44 2075943468


_______________________________________________
firedrake mailing list
firedrake@imperial.ac.uk
https://mailman.ic.ac.uk/mailman/listinfo/firedrake


--
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