[firedrake] hybridisation and tensor-product multigrid

[Lawrence Mitchell]

On 16 Mar 2015, at 02:49, Eike Mueller <E.Mueller at bath.ac.uk> wrote:

> (2) The other ingredient we need for the Gopalakrishnan and Tan approach is a tensor-product solver in the P1 space. So can I already prolongate/restrict in the horizontal-direction only in this space? I recall that Lawrence wrote a P1 multigrid, but I presume this is for a isotropic grid which is refined in all coordinate directions. Again I can probably do it 'by hand' by just L2 projecting between the spaces, but this will not be the most efficient way. Getting the columnwise smoother should work as for the DG0 case: I need to assemble the matrix locally and then pick out the vertical couplings and build them into a columnwise matrix, which I store as a vector-valued P1 space on the horizontal host-grid.

No, you should be able to do grid transfer for any horizontal x vertical point evaluation discretisation, as long as you only coarsen in the horizontal i.e.


m = BaseMesh(...)

mh = MeshHierarchy(...)

extruded_hierarchy = ExtrudedMeshHierarchy(mh, layers=...)

Lawrence
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 455 bytes
Desc: Message signed with OpenPGP using GPGMail
URL: <http://mailman.ic.ac.uk/pipermail/firedrake/attachments/20150316/cb9c4caf/attachment.sig>