Abstract
We present numerical results with a variable block multilevel incomplete LU factorization preconditioners for solving sparse linear systems arising, e.g., from the discretization of 2D and 3D partial differential equations on unstructured meshes. The proposed method automatically detects and exploits any available block structure in the matrix to maximize computational efficiency. Both sequential and parallel experiments are shown on selected matrix problems in different application areas, also against other standard preconditioners.