Ecient Management of Parallelism in Object-Oriented Numerical Software Libraries

ABSTRACT Parallel numerical software based on the message-passing model is enormously compli-cated. This paper introduces a set of techniques to manage the complexity, while maintaining high eciency and ease of use. The PETSc 2.0 package uses object-oriented programming to conceal the details of the message passing, without concealing the parallelism, in a high-quality set of numerical software libraries. In fact, the programming model used by PETSc is also the most appropriate for NUMA shared-memory machines, since they require the same careful attention to memory hierar-chies as do distributed-memory machines. Thus, the concepts discussed are appropriate for all scalable computing systems. The PETSc libraries provide many of the data structures and numerical kernels required for the scalable solution of PDEs, oering performance portability.