Sparse matrix inverse factors [power systems]

The structural and computation properties of the sparse matrixes encountered in various power system network analysis problems are discussed. Specifically, the inverses of the factors of sparse matrixes produced by factorization or decomposition are discussed. These inverse factors are themselves sparse, at least under suitable ordering and partitioning, and lend themselves to parallel operations in the direct or repeat solution phase of sparse matrix problems. Partitioning reduces the buildup of nonzero elements in the inverse factors, and parallel computation reduces the number of serial steps in the multiplications