trlan

Thick-restart Lanczos method for eigenproblems

This portable, modular Fortran 90 software package implements the thick-restart Lanczos method, for use with real symmetric or complex Hermitian eigenvalue problems where a small number of eigevalues and eigenvectors are needed, and the matrices involved may be too large to store in computer memory. Most of the arithmetic computations in the software are done through calls to BLAS and LAPACK. The software can be instructed to write checkpoint files so that it can be restarted is a later time.