Lis (Library of Iterative Solvers for linear systems, pronounced [lis]) is a parallel software library for solving linear equations and eigenvalue problems that arise in the numerical solution of partial differential equations using iterative methods.
The installation of Lis requires a C compiler. The Fortran interface requires a Fortran compiler, and the algebraic multigrid preconditioner requires a Fortran 90 compiler. For parallel computing environments, an OpenMP or MPI library is used. Both the Harwell-Boeing and Matrix Market formats are supported to import and export user data.