Timo,
> you can use dealii::SolverGMRES with a PETSc block matrix, even in
> parallel. There are many options to precondition this matrix. Block
> triangular or block diagonal preconditioners using the schur
> complement come to mind (elman, wathen, ...).
Generally speaking yes, but apparently I can't because the PETScWrappers
do not have a vmult () function for BlockVectors. (It turns out it works
fine for Vector like you say). There are some very versitile possibilities
that go with that interface (and related dealii::SolverXXXs).
Nevertheless, I am excited about this feature; ie. that I am not
restricted to PETSc's own solver interface just because I use PETSc
matrices (ie the interface in petsc_solver.*). This absolutely has to be
stated somewhere very clearly in the PETSc solver documentation (or
somewhere else); I don't think I can be the only one who has made this
incorrect (naive) assumption.
Thanks for the enlightment.
Best,
Toby
-----
Toby D. Young
Assistant Professor
Institute of Fundamental Technological Problems
Polish Academy of Sciences
ul Adolfa Pawinskiego 5b
02-106 Warsaw
Poland
www: http://www.ippt.gov.pl/~tyoung
skype: stenografia
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