dolfin team mailing list archive

[Johan Jansson <jjan@xxxxxxxxxx>]

Shilpa Khatri wrote:
> I would also like to know how this is done (We are using the c++ 
> interface). 
> Thanks,
> Shilpa 
>
> On Feb 13, 2008 4:09 PM, Kristen Kaasbjerg <cosby@xxxxxxxxx 
> <mailto:cosby@xxxxxxxxx>> wrote:
>
>     Hi,
>
>     I have a rather simple question - having obtained a FEM
>     solution "u" of a given PDE, how does one get the
>     function value at an arbitrary point "x" (I'm using the
>     python interface) ?
This functionality existed in DOLFIN a while ago, but it needs updating 
to new interfaces. Take a look at the old implementation:

http://www.fenics.org/hg/dolfin?f=50aee5576fed;file=src/kernel/function/DiscreteFunction.cpp

The point evaluation function is:

real DiscreteFunction::operator()(const Point& p, uint i)

The significant change that needs to be done is how to compute basis 
functions. This functionality now exists for general finite elements in 
the UFC interface (evaluate_basis()).

 Johan