  Multigrid methods are well suited to large massively parallel computer
architectures because they are mathematically optimal and display excellent
parallelization properties. Since current architecture trends are favoring
regular compute patterns to achieve high performance, the ability to express
structure has become much more important. The hypre software library provides
high-performance multigrid preconditioners and solvers through conceptual
interfaces, including a semi-structured interface that describes matrices
primarily in terms of stencils and logically structured grids. This paper
presents a new semi-structured algebraic multigrid (SSAMG) method built on this
interface. The numerical convergence and performance of a CPU implementation of
this method are evaluated for a set of semi-structured problems. SSAMG achieves
significantly better setup times than hypre's unstructured AMG solvers and
comparable convergence. In addition, the new method is capable of solving more
complex problems than hypre's structured solvers.
