Direct methods for spectral approximations in nonconforming domain decompositions

The application of a conforming spectral collocation method to certain nonconforming domain decompositions leads to global matrices which have a particular block structure. We study the performance of various direct linear system solvers, some of which exploit this block structure, on a Cray J-916 vector computer, an SGI Power Challenge 8000, and an IBM RS6000 workstation.