Acceleration of the convergence of a non-overlapping domain decomposition method by an approximate deflation technique for high-frequency wave propagation

The analysis of a non-overlapping domain decom- position method with optimized transmission conditions, applied to a simplified 1-D problem discretized by finite elements, is performed to better understand the spectral properties of the method. An approximate deflation preconditioner is then introduced to modify the spectrum of the iteration operator, and speed up the convergence of the GMRES algorithm used to solve the substructured problem.