Re: [Getfem-users] `Coupling Equations

[Yves Renard]

Dear Franz,

if I understand well, you compute some matrices such as
\int grad(u).grad(v)dx to perform the coupling.

There is no brick for the moment wich implement this. To build such a brick is 
a rather easy task, but if you don't want to do it you can use the "explicit 
matrix" brick which allows in particular to add a coupling term between two 
variables.


Without the model framework, it may be possible to build an iterative scheme 
allowing not to solve the whole linear system on the two variables, but at the 
time, I don't have an idea what should be this iterative scheme.

Yves. 
 


On lundi 26 septembre 2011, Pichler, Franz wrote:
> Hello everybody,
> I just get started with getfem and have some questions. What I want to do
> is to couple several equations. A minimal example of that would be
> something like:
> 
> Div(a1 \grad u) + Div(b1 \grad v) =g1
> Div(a2 \grad u) + Div(b2 \grad v) =g2
> 
> That with some Dirichlet condition on the interval [0,1]
> 
> Now I managed to do something like this buy taking the non model framework
> and assemble some matrices with the asm elliptic tools and put these
> matrices together by "hand". What I am wondering now is
> 
> 1) Is there a brick that I can tell that in my equation there are two
> variables with a laplacian (elliptic) term? 2) If I would try to write
> this brick myself, would I have to do it in c++ (I am using the python
> interface) 3) Is there a way of assembling this without the model
> framework and without putting the matrices together "by hand"
> 
> I would like to do all of this as time efficient as possible because in the
> end I want to solve time dependent problems with nonlinear terms.
> 
> Thank you very much in advance ,
> Franz Pichler
> 
> 
> 
> _______________________________________________
> Getfem-users mailing list
> address@hidden
> https://mail.gna.org/listinfo/getfem-users


-- 

  Yves Renard (address@hidden)       tel : (33) 04.72.43.87.08
  Pole de Mathematiques, INSA-Lyon             fax : (33) 04.72.43.85.29
  20, rue Albert Einstein
  69621 Villeurbanne Cedex, FRANCE
  http://math.univ-lyon1.fr/~renard

---------