[SciPy-dev] the scipy mission, include finite element solver

Daniel Wheeler daniel.wheeler2@gmail....
Thu Apr 9 10:25:27 CDT 2009


On Wed, Apr 8, 2009 at 6:43 PM, Ondrej Certik <ondrej@certik.cz> wrote:
> On Mon, Apr 6, 2009 at 8:58 AM, Daniel Wheeler
>> One weakness right now is that there doesn't seem to be a good open
>> source python based meshing tool. Again, this is not something that
>> should necessarily be in scipy, but something that should probably
>> leverage from scipy. We (FiPY) currently use gmsh, but it is not
>> tightly integrated and and we've written our own standard mesh
>> classes, but haven't done anything more with this.
>
> I like the FiPy project, when I get more time, I'd like to create some
> unified interface, so that one can take one equation and solve it with
> both FiPy and our FEM code (or libmesh), so that one can compare all
> those solvers and see which one performs the best.

Essentially, this is what we are trying to do with fipy. We would like
to access solvers from various packages via a common interface
(pysparse, scipy, trilinos, pykrylov, petsc, pyamg) and also call a
number of tools that construct matrices with different techniques. The
second part is harder to abstract and we only have our simple FV
method at the moment.

> Can FiPy do adaptive mesh refinement?

No. We'll wait until there is a meshing tool that can deal with it or
create a python interface to an existing tool at a push.

> I was trying to find it in the
> manual, but it seems you always need to create the mesh beforehand?

True.

> Then you calculate on it, you get something. How do you know if it's
> precise enough and if you should refine the mesh? How do you determine
> where you should refine it and how much?

Not something that fipy deals with at the moment. Basically it's a
task left to the user.

> If our FEM solver creates a nice hp mesh automatically, imho you
> cannot beat it by any hand made mesh, so then any comparison with a
> hand made mesh would be unfair to fipy.

Very true. h refinement is what we would like, but we require a third
party tool for this. The scope is too wide for us right now to deal
with.

-- 
Daniel Wheeler


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