Hierarchically spectral algebraic multigrid method for electromagnetic scattering

A novel spectral algebraic multigrid (SAMG) method is developed for solving electromagnetic scattering problems. Unlike traditional algebraic multigrid methods, the SAMG is an algebraic two-grid cycle built on a preconditioned iterative method that is used as the smoother, and the grid transfer operators are defined using the spectral information based on high-order hierarchical basis functions. Numerical results show that this method is very effective in electromagnetic scattering and can reduce overall simulation time significantly.