[petsc-dev] Petsc Support for Bandwidth Minimization

[Dave Nystrom]

I have a csr 2d finite difference matrix where the coordinates are (r,z).  It
is banded where the inner bands represent the r-coupling and the outer bands
represent the z-coupling.  I have been experimenting with using a separate
preconditioning matrix.  With the current ordering of unknowns, if I extract
the part of the csr matrix that represents the r-coupling, I have a compact
tridiagonal matrix.  If I extract the part of the csr matrix that represents
the z-couping, I have a tridiagonal matrix with a large, non-compact
bandwidth.

I'm wondering if petsc has support for reordering the unknowns under the hood
so that for the z-coupling case, the matrix can be cast as a compact
tridiagonal matrix.  Essentially, this would be support for minimizing the
bandwidth.

Thanks,

Dave