Hi Lawrence,

thanks, this fixes my problem and gets rid of the AttributeError. With the ,ultigrid-extrusion branch I can now successfully use the lowest order multigrid to preconditionen the iterative pressure solver both in 1+1d and 2+1d.

So essentially the idea of using the diagonally lumped mass matrix in the horizontal and using SPAI to lump in the vertical works, at least for small problems.

Cheers,

Eike

--

Dr Eike Hermann Mueller
Research Associate (PostDoc)

Department of Mathematical Sciences
University of Bath
Bath BA2 7AY, United Kingdom

+44 1225 38 5803
e.mueller@bath.ac.uk
http://people.bath.ac.uk/em459/

On 22 Dec 2014, at 17:04, Lawrence Mitchell <lawrence.mitchell@imperial.ac.uk> wrote:


On 22 Dec 2014, at 15:54, Eike Mueller <e.mueller@bath.ac.uk> wrote:

Hi Miklos,

thanks, I've done that now, and successfully updated my master. I still get the strange AttributeError for the element object. I updated ufl, checked that I am using the correct version and blew all firedrake caches by running scripts/firedrake-clean.

what's odd is that element does seem to have the attribute I'm asking for:

FWIW, if you want 1+1d, you'll want the multigrid-extrusion branch.  This also removes special casing of DG0 so that error you have may disappear (you can also try, if you like) just restricting DG1 directly (rather than doing hp-MG).

Lawrence
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