dolfin team mailing list archive

["Garth N. Wells" <gnw20@xxxxxxxxx>]

On 16/02/11 16:54, Johan Hake wrote:
> Question #145534 on DOLFIN changed:
> https://answers.launchpad.net/dolfin/+question/145534
> 
> Johan Hake proposed the following answer:
> On Wednesday February 16 2011 08:48:38 Anders Logg wrote:
>> Question #145534 on DOLFIN changed:
>> https://answers.launchpad.net/dolfin/+question/145534
>>
>>     Status: Open => Answered
>>
>> Anders Logg proposed the following answer:
>>
>> On Tue, Feb 15, 2011 at 10:30:06PM -0000, Yi Jiang wrote:
>>> New question #145534 on DOLFIN:
>>> https://answers.launchpad.net/dolfin/+question/145534
>>>
>>> Hi all,
>>>
>>> I am using the dolfin to solve a PDE problem by finite element method.
>>> However, I met a problem when I try to define the linear form L(v) of
>>> right hand side. Suppose the PDE is:
>>>
>>> F(x) = f.
>>>
>>> What should I do if the f is a Dirac Delta function. How to define it in
>>> ufl? Anybody met and solved the similar problems before?
>>> Thank you for attention and kind help.
>>
>> This is not supported.
> 
> I am also interested in this. What would it require to implement? Changes to 
> UFL, FFC, DOLFIN?
>

A lot of changes. It would require being able to integrate over
surfaces/lines within a cell.

UFL can be stretched to do this, but extentions to FFC and DOLFIN are
needed. Take a look at the modelling discontinuities chapter in the
FEniCS book ;).

Garth


> Johan
>