I have to solve an Eigenvalue problem originating from the Electrodynamics. It is a 2-D problem with a rectangular region. More specifically, there is a hole on a rectangle made by magnetic material. This problem should be solve by the "NDEigensystem". Due to the irregular region, it can only be solved by the method "PDEDiscretization", such as Finite Element Method; however, it seems that I cannot monitor the mesh which is important to the solution accuracy. For example, I don't know how to check the mesh around the hole, where the mesh should be denser. On the contrary, in "NDSolve" there are much more commands for the mesh so one can easily check the mesh quality of the solution region.
So I would like to know is it possible to apply the meshing command such as "ToElementMesh" in "NDEigensystem" to control the mesh quality? Thank you.
Thank you for your help. It works. Additional question: For a 1D Eigenvalue problem with the interval composed of different materials, is it necessary to assign the positions of the interface points? (According to the suggestions, these contents have been posted elsewhere. Interface points of NDEigensystem)