Hello everyone, I’ve been playing around with FF++ to solve some problems quite successfully. We are using a hybrid discontinuous Galerkin formulation. Currently, we are solving a time-dependent Cahn-Hilliard-like problem. However, we were not able to implement the static condensation (Schur compl…

What do you want to do efficiently? Static condensation or solving Cahn–Hilliard equation?

Sorry if the message was confusing. I would like to perform the static condensation. The CH code is working, but without static condensation.

To day they no sparse static condensation in FreeFem++ in fact you want to eliminate of internal dof of the formulation. Il is not to hard of code with the HashMatrix, it is the same ShurComplement.cpp algorithm of plugin but the result is a sparse matrix (ie. a hash matrix in freefem++) the onl…

Thanks a lot for the reply. In fact I notice it would be difficult to do it on the element level. And later on I found this link: FreeFem/FreeFem-sources/blob/develop/examples/hpddm/Schur-complement-PETSc.edp // run with MPI: ff-mpirun -np 1 script.edp // NBPROC 1 assert(mpisize == 1)…

There are a lot of PETSc things to help you out. You could also use a fieldsplit preconditioner, and approximate the Schur complement, see this documentation page.

Static condensation for hybrid discontinuous Galerkin methods

General Discussion

prj July 29, 2020, 4:48pm 4

You want to do static condensation on each element? Or for the global system?

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Static condensation for hybrid discontinuous Galerkin methods

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