Advances in Multigrid Solution of 3D Forward MCSEM Problems

In this note we concentrate on iterative solution of the linear algebraic systems resulting from the finite-difference discretization of 3D forward mCSEM simulation. We review and test a recently developed multigrid preconditioner to an iterative solver and introduce some changes into the smoothing scheme of the multigrid algorithm. We substitute the originally used symmetric multiplicative Schwarz smoothing scheme with that of additive Schwarz. We also found an approximately optimal value for the scaling factor needed for additive Schwarz smoothing. Our changes result in a faster and naturally parallelizable algorithm.