General Sparse Elimination Requires No Permanent Integer Storage

Abstract

General sparse elimination is designed to take maximum advantage of the sparsity of an $N \times N$ matrix ${\bf A}$. Only the nonzeros of ${\bf A}$ are stored, along with some extra integer overhead to identify the nonzero matrix elements. This extra integer storage may be avoided for the triangular factors generated by an ${\bf {LDU}}$ decomposition, generally without increasing the order of complexity. In addition to permanent storage for the nonzero elements of the factors, our procedure requires at most $5N$ temporary integer storage.