The one-and-only algorithm for em-field computations does not exist

Today there are numerous approaches to solve Maxwell´s equations for practical cases. There are discretization methods using volume or surface meshes. The local approximation of Maxwell´s equations may be performed by the finite element method, the finite difference method or the finite integration technique, to name only the most commonly used ones. None of the known techniques is able to solve the full range of practical problems that are attacked today. Although in principle, almost all tools could solve all problems, for each specific class of problems, there exists an optimal algorithm. We will demonstrate for a relatively simple waveguide that the computational effort compared between different methods may vary in orders of magnitude.