Package Name LANCZOS
Author(s) Jane Cullum and Ralph Willoughby
Version version number not available
Date 1984, updated 1992
Language Fortran 77
Platform(s) any
Reference 4.4 Lanczos Method
Functionality The LANCZOS package contains algorithms for real symmetric, generalized real symmetric, Hermitian, singular value, and complex symmetric problems. The block Lanczos algorithms invoke an implicit deflation of the Lanczos vectors which is achieved by reorthogonalization w.r.t. certain well-chosen vectors. However, the 'single-vector' algorithms function with no reorthogonalization of the Lanczos vectors and thus can be used on huge problems.

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