[CIG-MC] coupler & multigrid solver?
mibillen at ucdavis.edu
Tue Aug 10 17:23:48 PDT 2010
I've been doing some test models using the coupler option, embedding a
regional mesh into a larger low resolution regional mesh.
I had the unpleasant surprise of finding this error message when I
tried to use the multigrid solver:
AssertionError: Error: solver.vsolver.Solver must be "cgrad"
Knowing how slow conjugate gradient is compared to multigrid for most
problems, this is a huge
disappointment - in particular because, as far as I can tell, its not
mentioned anywhere in the manual.
So, I'm wondering why doesn't the coupler work with multigrid? Is this
something that should work,
but hasn't been tested, or is there something about how the
information gets past between the
coupled models that prevents the use of the multigrid solver?
Given how slow conjugate gradient is, it seems that any benefit from
using less nodes by embedding meshes will be completely lost by
having to use the conjugate gradient solver instead of multigrid.
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