On Computing Certain Elements of the Inverse of a Sparse Matrix A recursive algorithm for computing the inverse of a matrix from the LU factors based on relationships in Takahashi, et al., is examined. The formulas for the algorithm are given; the dependency relationships are derived; the computational costs are developed; and some general comments on application and stability are made. CACM March, 1975 Erisman, E. M. Tinney, W. F. sparse matrices, triangular factorization, elements of inverse, tridiagonal matrix, sensitivities 3.24 5.14 CA750308 JB January 9, 1978 4:34 PM 2780 5 2780 2780 5 2780 2780 5 2780