On Thu, May 30, 2013 at 09:42:12AM +0200, Martin Sandve Alnæs wrote:
> On 30 May 2013 09:34, Johan Hake <[1][email protected]> wrote:
>
> Hi Marco!
> DOLFIN use SWIG to create Python wrappers. SWIG provides Octave
> wrappers
> too. Are you going to use those?
> [2]http://www.swig.org/Doc2.0/SWIGDocumentation.html#Octave
> SWIG use a flat namespace for the generated wrapper code, so you
> would
> still have nameclashes for the Array class. However it will
> internally
> keep all original C++ type information. SWIG also allows you to
> rename
> any C++ entity, classes, functions, variables, methods, aso, to
> whatever
> in the target language. You can then just tell SWIG to rename the
> dolfin::Array to, let say, dolfin::ArrayDolfin.
> Another challenge you might consider before you invest too much is
> to
> figure out how you should integrate the code generation part of
> FEniCS.
> For now that is handled by the Python packages of FFC, FIAT, UFL,
> and
> parts of UFC. Because these are all in Python we have been able to
> integrate these seamlessly (but not without bumps) with the Python
> interface of DOLFIN.
>
>
> Doing this within octave will be challenging.
>
> To say the least... I'd say it's close to impossible to get the same
> level of integration with just in time compilation as we have in
> python.
> However if it's possible to wrap pregenerated forms (i.e. header files
> generated by running ffc on the commandline) it could be useful to
> assemble matrices directly in octave for analysing eigenvalues etc. In
> some older internal code here at Simula we had the concept of a "matrix
> factory" which could assemble common matrices from a number of
> pregenerated form files, e.g. mass, stiffness, convection etc.
A matrix factory approach sounds like a very good fit for Octave. I
suggest using that approach and implementing an extensive list of
"finite element matrices" for various degrees of polynomials and
possibly different element families.
An alternative, if you can live with calling Python from within the
internals of your Octave package, would be to work with strings that
are passed to Python. So you could do something like
mesh = <some Octave data structure for a mesh like (p, e, t)>
A = fem_matrix("dot(grad(u), grad(v))*dx, mesh, "P1")
--
Anders
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