Re: [ff3d-users] Building matrices with ff3d

[Stephane Del Pino]

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Le mardi 4 Mai 2004 15:40, thomas.gazzola a écrit :
> Hello to everyone !
>
> I have a few questions about ff3d :
>
> 1) Is it possible to make unregular structured meshes directly
> with ff3d ? Or shall I import a mesh build with an other program ?
No. You must provide an unstructured mesh *or* use the fictitious domain 
solver.

> 2) Are P2 elements available, or only P1, as I read on a
> previous mail ?
No. And they won't be in release 1.0.

> And the main question :
> 3) With FreeFEM++, I could build matrices resulting from
> variational forms, by typing this (for example) :
ff3d is also to you to provide such features. It will be possible in the 
future, but when?
> // Bilinear variational form a
> varf  a(u1,u2)= int2d(Th)( dx(u1)*dx(u2) + dy(u1)*dy(u2) ) ;
> // matrix A created from the variational form a, on the FE
> space Vh
> matrix A = a(Vh,Vh);
>
> Then I can make my own loops, for non-linear problems (in my
> case, an optimization problem).
> So the question is (of course :o)), is it still possible with
> ff3d ?
You can of course solve non-linear problems using loops, but you cannot access 
the matrix itself.

Regards,
Stephane.
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