Oges User Guide, Version 2.0, A Solver for Steady State Boundary Value Problems on Overlapping Grids

Abstract: We describe the Overture class Oges, an “Overlapping Grid Equation Solver”, that can be used for the solution of sparse matrix equations on overlapping grids such that those created by the grid generator Ogen. Oges acts as a front end to a variety of sparse matrix solvers including direct sparse solvers such as those from Yale or Harwell or iterative solvers (from SLAP and PETSc) that use algorithms such as conjugate gradient or GMRES. To use Oges one must first generate a a system of equations (usually defining a PDE boundary value problem) using the ‘coefficient matrix ’ grid functions and the Overture operator classes. Oges will take a coefficient matrix generated in this way and then call the appropriate sparse matrix solver. Oges can be easily extended to use a new Sparse matrix package