Spectral element agglomerate algebraic multigrid methods for elliptic problems with high-contrast coefficients

We apply a recently proposed ([3]) robust overlapping Schwarz method with a certain spectral construction of the coarse space in the setting of element agglomeration algebraic multigrid methods (or agglomeration AMGe) for elliptic problems with high-contrast coefficients. Our goal is to design multilevel iterative methods that converge independent of the contrast in the coefficients. We present simplified bounds for the condition number of the preconditioned operators. These bounds imply convergence that is independent of the contrast. In the presented preliminary numerical tests, we use geometric agglomerates; however, the algorithm is general and offers some simplifications over the previously proposed spectral agglomerate AMGe methods (cf., [1, 2]).