Re: [Geopdes-users] GeoPDEs multipatch

[Giulia <giu...@gm...>]

Hi Rafael,

Thank you for the answers.
I downloaded the manifolds branch at this address:
http://sourceforge.net/p/geopdes/code/HEAD/tree/branches/manifolds/

But if I run the "Laplace-Beltrami problem on a 3D surface" example, I get
the error "Undefined function 'max' for input arguments of type 'cell'." in
findspan() called inside sp_drchlt_l2_proj().

Is this normal because I am using a beta version, or should it work?

Thank you,

Giulia

On Mon, Apr 27, 2015 at 10:56 AM, Rafael Vazquez <va...@im...>
wrote:

> Hi Giulia,
>
> On 24/04/2015 20:31, Giulia wrote:
>
>> Hi everyone,
>>
>> is there any reference or documentation on how GeoPDEs multipatch works?
>>
> There is no special documentation for multipatch problems, only what is
> written in the technical report. Basically, we assume that the patches
> match conformingly, that is, on the interface they have the same knot
> vector (up to an affine transformation) and they share the same control
> points. With that, the functions are easily glued together with C^0
> continuity, since one function from one patch corresponds to another
> function in the other patch. You can generate the information to deal with
> multipatch geometries using the function nrbmultipatch from the nurbs
> toolbox.
>
>>
>> Is it possible to control the regularity of the solution between different
>> patches and along the interfaces?
>>
> In geopdes we have only implemented the C^0 case, for higher regularity
> you will have to implement that yourself. Notice that you will need the
> derivatives on the boundary, which is not contained in the boundary
> structures as they are now. To get the derivatives on the boundary you can
> use the same approach that we have already used to impose the boundary
> conditions in a weak form, in the function sp_weak_drchlt_bc of the
> geopdes_fluid package.
>
>
>> In a previous thread I read that someone made GeoPDEs work with 3D
>> surfaces. Do you know if and where I can find an example of that?
>>
> Actually, I am preparing a new version of geopdes that works with 3D
> surfaces. You can already download it from our sourceforge repository
> (packages base, elasticity and multipatch), but be aware that it is still a
> beta version. Otherwise, you can try to contact the users that have already
> implemented 3D surfaces in the current version.
>
> I hope this helps,
> Rafa
>