ARPACK-NG is a collection of Fortran77 subroutines designed to solve large
scale eigenvalue problems.

Important Features:

    o  Reverse Communication Interface.
    o  Single and Double Precision Real Arithmetic Versions for Symmetric,
       Non-symmetric, Standard or Generalized Problems.
    o  Single and Double Precision Complex Arithmetic Versions for Standard
       or Generalized Problems.
    o  Routines for Banded Matrices - Standard or Generalized Problems.
    o  Routines for The Singular Value Decomposition.
    o  Example driver routines that may be used as templates to implement
       numerous Shift-Invert strategies for all problem types, data types
       and precision.
    o  ILP64 support

No arpack release has been published by Rice University for many years, and
arpack-ng aims to provide a common repository of community fixes with a
testsuite.