[petsc-users] computation of Sp for fieldsplit schur preconditioner
Luc Berger-Vergiat
lb2653 at columbia.edu
Wed Dec 3 10:20:46 CST 2014
Hi all,
I would like to know if there would be an easy way of computing the Sp
preconditioner for a fieldsplit schur complement using the following
formula:
Sp=A11-A10*diag(inv(A00))*A01
instead of
Sp=A11-A10*inv(diag(A00))*A01
I think that it would be really beneficial in my case since the
eigenvalues of both operators are very different for my problem (see
ev_S_diaginv for the eigenvalues of the modified Sp and ev_S for the
eigenvalues of the current Sp).
I do understand that this requires to compute a more complex inverse
while forming Sp, but I compute this inverse using a block jacobi lu due
to the special properties of my matrix (see jac_nonlin_nested for the
sparsity pattern of my matrix). So the change would actually be quite
minimal no? I am also actually debating whether I should compute the
exact S?
--
Best,
Luc
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