Partitioning Sparse Rectangular Matrices Tamara G. Kolda Oak Ridge National Laboratory Matrix partitioning is used to reduce communication and balance the workload in parallel computations involving sparse matrices. Substantial effort has gone into developing partitioning schemes and software for sparse, structurally symmetric matrices. However, scant attention has been paid to the rectangular and structurally nonsymmetric cases. Rectangular and structurally nonsymmetric matrices arise in many situations including the solution of nonsymmetric linear systems, large-scale SVD computations, linear programming, etc. We will present a bipartite graph model for partitioning rectangular matrices and describe new methods for partitioning this type of graph with numerical results. Lastly, we'll discuss the matrix partitioning problem in general and new work that is going on in the area. (This is joint work with Bruce Hendrickson of Sandia National Labs.)