Does it exist a way to apply weighted displacement from master point x to slave point y with periodicBC ?

This is not possible at the moment, but periodic BCs are up for
redesign and will likely support more general periodic boundary
conditions, such as letting a user explicitly mark (via for example a
MeshFunction) which dofs should be identified as periodic.

--
Anders

On Tue, Oct 30, 2012 at 02:55:58PM -0000, Abdallah Ben Othman wrote:
> Question #212757 on DOLFIN changed:
> https://answers.launchpad.net/dolfin/+question/212757
>
> Description changed to:
> Dear all,
>
> According to the periodicBC documentation, DOLFIN is able to apply
> periodic boundary condition such that :
>
> u(x) = u(F^{-1}(x)) on G,
> u(x) = u(F(x)) on H,
>
> And I would like to add another member to this equation such that :
>
> u(x) = u(F^{-1}(x)) + E(x-F^{-1}(x)) on G,
> u(x) = u(F(x)) + E(x-F(x)) on H,
>
> With E a given tensor.
>
> So, if someone has already worked on this question or if someone have an idea, may
> she/he help me, please ?
>
> thanks for your help and your attention,
> Abdallah.
>

Thank you Anders Logg for your response,

I implemented an other class ExtendedPeriodicBC which extends the PeriodicBC in c++ for dolfin 1.0
This class is able to do what I need, as I explain previously. Even if the source code is not as clean as I want
(I had to hack some class visibilities), it works perfectly well.

I didn't submit this new class for a possible integration because I knew version 1.1 will be published.

I use this class to solve a multi-scale problem, and I need to use more than one periodic boundary condition on
the same mesh. It seems to be impossible with the version 1.1.

Is there a way to define two, three or more periodic boundary conditions, with c++ interface ?
And with the new periodic boundary condition, How could I add the second part of equation ?
(If I can't I will try to make my own extended class and if it works I will submit it).

Thanks for your help,
Abdallah Ben Othman.