Hello,

I’m trying to figure out the “best” way to normalize a resulting grid function on a subsection of the mesh. For the purposes of this topic I’m considering an Eigenvalue-Problem similar to 1.7.1 in the tutorial (1.7.1 Perfectly Matched Layer (PML) — NGS-Py 6.2.2302-87-ga5a5eff3b documentation).

The geometry is as follows:

```
geo = SplineGeometry()
geo.AddCircle( (0.0, 0.0), r=1.0, leftdomain=1, rightdomain=2, bc = "scatterer")
geo.AddCircle ( (0.0, 0.0), r=2.0, leftdomain=2, rightdomain=3)
geo.AddCircle ( (0.0, 0.0), r=3.0, leftdomain=3, rightdomain=0,bc = "dir")
```

I’ve modified the Arnoldi solver to output only the eigenvalue I want and have the resulting gridfunction u associated with it. However, I want to normalize u only on region 1.

Do I need to define a new mesh that only covers region 1 to integrate it or is there a way to restrict the integral only to the first region?

Thanks,

AJ