Prolongation operator for SurfaceL2

General
1

Hi,

I would like to follow 2.1.3 Multigrid and Multilevel Methods — NGS-Py 6.2.2304 documentation in order to build my own multilevel preconditioner.
I have a Bilinearform (based on BEM, but that’s a different story) which is given on a SurfaceL2 space. Now i would like to use fes.Prolongation() but the method always returns None. Is prolongation not implemented for surface spaces? is there any workaround (the mesh I’m using is the trace of a Volume mesh if this helps)?

Minmal example:

from ngsolve import *

mesh = Mesh(unit_square.GenerateMesh(maxh=0.3))

fes = SurfaceL2(mesh,order=1, dirichlet=".*", autoupdate=True)
u,v = fes.TnT()
a = BilinearForm((u)*(v)*ds)

mesh.Refine()

print(fes.Prolongation())

best,
Alex

2

Hi Alexander,

for SurfaceL2(order=0) there is now a prolongation operator !

Joachim