PETSc and overture : lessons learned developing an interface between components.

We consider two software packages that interact with each other as components: Overture and PETSc. An interface between these two packages could be of tremendous value to application developers in that Overture provides a simple mechanism for generating the large, sparse systems of linear equations that correspond to discretizations of a PDE, and PETSc provides a powerful collection of methods for solving these systems. Two types of interfaces are discussed: the internal interface between components, and the external interface for the application developer. We compare three basic approaches to developing the internal interface between Overture and PETSc, the final one of which is a peer-to-peer model