Question #99875 on DOLFIN changed:
https://answers.launchpad.net/dolfin/+question/99875
Status: Open => Answered
Anders Logg proposed the following answer:
On Thu, Feb 04, 2010 at 12:08:58PM -0000, dbeacham wrote:
> New question #99875 on DOLFIN:
> https://answers.launchpad.net/dolfin/+question/99875
>
> I think I'm right in thinking that dolfin can only perform n-dimensional
> calculations on meshes embedded in R^n, however is there an easy way to
> restrict the dof/manipulate the assembly such that when I do something like
>
> a = u*v*ds
> L = f*v*ds
>
> the assembled forms have non-zero determinant? Currently the assembly gives
> these matrices (reordered):
> [ds stuff | 0 ]
> A= [------------------]
> [ 0 | 0 ]
> [ds stuff ]
> b= [----------]
> [ 0 ]
>
> whereas I'd either like to just keep the ds stuff (although that would
> require another mapping between the reordered ds nodes and the original mesh)
> or possibly set the bottom right of A to the identity matrix (without having
> to manipulate the matrix myself).
>
> Alternatively, are there any better approaches I could adopt?
I don't know of a way other than to assemble the matrices and then
extract the relevant portions into a new matrix.
We have had some support earlier for restriction of the global set of
dofs to a subset but that has been broken for a while.
--
Anders
--
You received this question notification because you are a member of
DOLFIN Team, which is an answer contact for DOLFIN.
_______________________________________________
Mailing list: https://launchpad.net/~dolfin
Post to : [email protected]
Unsubscribe : https://launchpad.net/~dolfin
More help : https://help.launchpad.net/ListHelp
