H2 norm for vector/function?

Question

Hi,

I need to calculate $$ H_{2} $$ norm for a function. At the moment it doesn't look like it is available yet for current version. Is there any plans it could be implemented in the future? Or is there a way to work around it?

Thanks,
Q

Answer 1

That would require C^1 (i.e. with continuous derivatives) elements, which is not yet available.
You may do it in a non-conforming way by including jump terms, see
eg.
https://bitbucket.org/fenics-project/dolfin/src/cacc59d74f8f0d836277d91e7d1a04dc64eb9476/demo/documented/biharmonic/python/demo_biharmonic.py?at=master&fileviewer=file-view-default

or in case you have an analytical expression, you may differentiate by hand or with ufl.