H1-P0 FEM

Hello everyone！

V = H1(mesh, order=0)
and
Vbar =H1(mesh, order=0, orderinner=0, dirichlet=[1,2,3,4])

Can these two finite element spaces be used？ and， do they have only one degree of freedom？

No the H1 space is only well defined for order >= 1. If you need a constant on the whole domain you can use the NumberSpace.
Best Christopher

Hi Christopher！

Now，can I define a constant on the skeleton？

Thanks！
Yongbin

The evaluator of the NumberSpace always returns the constant, so you should be able to use it in a skeleton formulation as well...
Did you try it?
Best
Christopher

Hi!
NumberSpace is the space V = FESpace("number",mesh) ?

Thanks！
Yongbin

Yes, better is the Python constructor: V = NumberSpace(mesh)
Best