A GenEO Domain Decomposition method for Saddle Point problems

We introduce an adaptive element-based domain decomposition (DD) method for solving saddle point problems defined as a block two by matrix. The algorithm does not require any knowledge of the constrained space. assume that all sub matrices are sparse and diagonal blocks spectrally equivalent to sum positive semi definite matrices. latter assumption enables design coarse space DD methods extends GenEO theory (Spillane et al., 2014) problems. Numerical results on three dimensional elasticity steel-rubber structures discretized finite element with continuous pressure shown up one billion degrees freedom.