Binary package “libarpack2” in ubuntu focal

Fortran77 subroutines to solve large scale eigenvalue problems

 ARPACK software is capable of solving large scale symmetric,
 nonsymmetric, and generalized eigenproblems from significant
 application areas. The software is designed to compute a few (k)
 eigenvalues with user specified features such as those of largest
 real part or largest magnitude. Storage requirements are on the order
 of n*k locations. No auxiliary storage is required. A set of Schur
 basis vectors for the desired k-dimensional eigen-space is computed
 which is numerically orthogonal to working precision. Numerically
 accurate eigenvectors are available on request.
 .
 Important Features:
 .
  * Reverse Communication Interface.
  * Single and Double Precision Real Arithmetic Versions for Symmetric,
    Non-symmetric,
  * Standard or Generalized Problems.
  * Single and Double Precision Complex Arithmetic Versions for Standard or
    Generalized Problems.
  * Routines for Banded Matrices - Standard or Generalized Problems.
  * Routines for The Singular Value Decomposition.
  * Example driver routines that may be used as templates to implement
    numerous Shift-Invert strategies for all problem types, data types and
    precision.
 .
 This package contains the shared library.