dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Tue, Oct 04, 2011 at 04:17:01PM +0100, Garth N. Wells wrote:
> On 4 October 2011 12:24, Anders Logg <logg@xxxxxxxxx> wrote:
> > SystemAssembler does not support subdomains. It is even silently
> > ignoring all other integrals than number 0.
> >
> > This is one of the remaining bugs for 1.0-beta2. I can try to fix it
> > but would like some input on what shape the SystemAssembler is
> > currently in. I haven't touched it that much before since it looks
> > like a bit of code duplication to me. In particular, is it necessary
> > to keep both functions cell_wise_assembly and facet_wise_assembly?
> >
>
> It would require some performance testing to decide. I expect that,
> for performance reasons, both are required.

I'm getting very strange results. Here are results for assembling
Poisson matrix + vector on a 32 x 32 x 32 unit cube:

  Regular assembler: 0.658 s
  System assembler:   9.08 s (cell-wise)
  System assembler:    202 s (facet-wise)

Is this expected?

What are the arguments against ditching SystemAssembler (for less code
duplication) and adding functionality for symmetric application of BCs
on the linear algebra level?

--
Anders