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[hetzel.devel@xxxxxx]

Hi Johan,
I don't want to create two matrices.
My bilinearform is defined like a(u,v), where u is a vector of u1 and u2. The same for v.
What I now need is the give the first component of the Vector u and  v another mesh then the second.
I need to solve a modified version of the Navier-Stokes PDE.
The reason is, that the first component is used to calculate a pressure. This needs to be calculated quite exactly so I need a mesh with many nodes.
The second component is the hight of my oil-thickness. But this mesh needs to be coupled with a quite rough mesh, of another calculation. Therfore I only have some nodes to work with.
The matrix will look like this
a=[ A B ]
    [ C D ]
With a look to the matrix there is no Problem to calculate the upper left corner A (2000x2000) and the lower right D (20x20), but I also need the coupling C and D so the 20x2000 and 2000x20 matrices.

/Haiko


Discussion of DOLFIN development <dolfin-dev@xxxxxxxxxx> schrieb am 09.11.05 15:02:06:
> 
> On Wed, Nov 09, 2005 at 10:48:37AM +0100, hetzel.devel@xxxxxx wrote:
> > 
> > Hi,
> > I'm having two functions say u1 und u2 and two test functions v1 and v2. At the moment I'm using the "Vector Lagrange" Functions to declare u and v as a vector.
> > 
> > I would like to solve my PDE with u1 and v1 defined on mesh1 (approx. 2000 nodes) and u2 and v2 defined on a different mesh2 (approx. 20 nodes). I would like to get a 2020x2020 matrix. Both meshes will be contain exectly the same area.
> > Is there a change to declare the bilinearform in such a manner?
> > 
> > /Haiko
> > 
> 
> Hi Haiko,
> 
> A form is not connected to a specific mesh, so it's perfectly ok to
> assemble the same bilinear form on two different meshes. But then you
> would get two different matrices. Why do you want the result in the
> same matrix? Isn't it ok to get matrix A1 (2000x2000) corresponding to
> the first mesh and matrix A2 (20x20) corresponding to the second mesh?
> 
>   Johan
> 
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