There are a few things to consider here:
- is your element type triangle/tetrahedra or quadrilateral/hexahedral
1b) are the mesh cells affine?
If no on 1b the degree is usually alot higher than in the affine case.
Consider a general affine simplex with a test/trial function of order Q. Then a mass matrix has order 2Q, while a stiffness matrix has order 2*(Q+1).
- How does the PML functions look like? In general you can use
How to obtain the Gauss quadrature degree estimated by the form compiler - #2 by dokken
to check what the estimated degree of various forms are.
Without an example on a square or cube with the forms (ignoring the subdomains of pml, just using regular dx), it is hard to give further pointers.