A guide to understanding and using the software package ARPACK to solve large algebraic eigenvalue problems. The software described is based on the implicitly restarted Arnoldi method, which has been heralded as one of the three most important advances in large scale eigenanalysis in the past ten years. The book explains the acquisition, installation, capabilities, and detailed use of the software for computing a desired subset of the eigenvalues and eigenvectors of large (sparse) standard or generalized eigenproblems. It also discusses the underlying theory and algorithmic background at a level that is accessible to the general practitioner. Other important topics covered include:* Treatment of the non-Hermitian problem.* Explanation of the theory behind Krylov subspace projection methods, implicit restarting, and spectral transformation.* Explanation of the implicitly restarted Arnoldi method (IRAM).* Descriptions of the various templates (driver routines) to interface an application with ARPACK to solve a wide variety of problems. ARPACK is a collection of Fortran 77 subroutines designed to solve large-scale eigenvalue problems.It provides state-of-the-art software for solving large (sparse) Hermitian, non-Hermitian, standard, or generalized eigenvalue problems from significant application areas. It is one of the few software packages to successfully address the non-Hermitian problem. Practitioners will be able to better understand the full capabilities of ARPACK (ARnoldi PACKage) and grasp the underlying theory more thoroughly with this book.