“…Thus, Linear multigrid methods have also been applied to linear systems that do not arise from partial differential equations, and often do not even have an underlying geometry [7]. This has been most successful for graph Laplacian matrices, which are in many ways an algebraic analogue to the geometric Poisson problem [16,33,34,10]. Algebraic multigrid, with its ever expanding area of application and intent for extreme scale parallel scalability, is still an active area of research [14,6,46,17,4].…”