dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Tue, Jan 15, 2008 at 10:22:41PM -0500, Gideon Simpson wrote:
> Scratch that.  I discovered COMSOL does something very nice that boosts the
> quality of its results.  If I have a curved boundary on my geometry, COMSOL
> will interpolate the associated quadrature on the cells along that boundary to
> improve accuracy.  When I turn that feature off, the results are consistent
> with what I'm getting from FEniCS.
> 
> But the question remains: are there any benchmarks?

I think Andy Terrel did a few benchmarks which were actually for
Stokes. Lot's of things have happened since, but if he reads this he
can probably point you to a copy of his master thesis on the subject.

Although I don't have any numbers, I expect the assembly of the linear
system to be very fast in DOLFIN (or we did something wrong and can
fix it).

For the linear solve, we just trust PETSc and the preconditioners
available there.

For the method, it's up to you to formulate it using any of the
elements available in DOLFIN. The speed/accuracy will depend on the
choice of element.

-- 
Anders


> 
> 
> -gideon
> 
> 
> On Jan 15, 2008, at 9:51 PM, Gideon Simpson wrote:
> 
> 
>     Has anyone done any benchmarking with dolfin?  
> 
>     I've been comparing some dolfin output to some problems I've previously
>     done using COMSOL and I have to tell you I'm not crazy about the results.  
>     In particular, I'm interested in linear Stokes flow problems around objects
>     that arise out of homogenization and I find that when I compute the domain
>     averages of the variables ( pressure, velocity ), as one does in such
>     problems, the convergence to a fixed value as the mesh is refined isn't so
>     good.  I've tried both iterative and direct solvers too.
> 
> 
>     -gideon
> 
>     _______________________________________________
>     DOLFIN-dev mailing list
>     DOLFIN-dev@xxxxxxxxxx
>     http://www.fenics.org/mailman/listinfo/dolfin-dev
> 
> 

> _______________________________________________
> DOLFIN-dev mailing list
> DOLFIN-dev@xxxxxxxxxx
> http://www.fenics.org/mailman/listinfo/dolfin-dev