Abstract. An efficient parallel algorithm is presented and tested for computing selected components of H−1 where H has the structure of a Hamiltonian matrix of two-dimensional lattice models with local interaction. Calculations of this type are useful for several applications, including electronic structure analysis of materials in which the diagonal elements of the Green’s functions are needed. The algorithm proposed here is a direct method based on an LDLT factorization. The elimination tree is used to organize the parallel algorithm. Synchronization overhead is reduced by passing the data level by level along this tree using the technique of local buffers and relative indices. The performance of the proposed parallel algorithm is analyzed by examining its load balance and communication overhead, and is shown to exhibit an excellent weak scaling on a large-scale high performance parallel machine with distributed memory. Key words. selected inversion, parallel algorithm, electron...