1. Purpose
-------
This directory contains example drivers that call ARPACK subroutines
[s,d]saupd.f and [s,d]seupd.f to solve SYMMETRIC eigenvalue problems
using regular, inverse, shift-invert or other special modes (such as
Cayley, Bucking etc.)
These drivers illustrate how to set various ARPACK parameters to solve
different problems in different modes. They provide a guideline on how
to use ARPACK's reverse communication interface. The user may modify
any one of these drivers, and provide his/her own matrix vector
multiplication routine to solve the problem of his/her own interest.
2. Naming convention
-----------------
The name for each driver has the form 'XsdrvN.f', where
X - is 's' (single precision)
or 'd' (double precision)
N - is a number between 1 and 6. If
N = 1, the driver solves a STANDARD eigenvalue problem in
REGULAR mode
N = 2, the driver solves a STANDARD eigenvalue problem in
SHIFT-INVERT mode.
N = 3, the driver solves a GENERALIZED eigenvalue problem in
INVERSE mode
N = 4, the driver solves a GENERALIZED eigenvalue problem in
SHIFT-INVERT mode.
These are 4 commonly used drivers. For shift-invert (N=2,4) mode
the user needs to supply a linear system solver to perform
y=inv[A-sigma*B]*x.
When N > 4, a special mode is used. If
N = 5, the driver solves a GENERALIZED eigenvalue problem in
BUCKLING mode.
N = 6, the driver solves a GENERALIZED eigenvalue problem in
CAYLEY mode.
These two drivers require the user to provide linear system
solvers also. For more information on Cayley and Buckling mode,
see the following reference:
R.G. Grimes, J.G. Lewis and H.D. Simon, "A Shifted Block Lanczos
Algorithm for Solving Sparse Symmetric Generalized Eigenproblems",
SIAM J. Matr. Anal. Apps., January (1993).
3. Usage
-----
To run these drivers, you may use the makefile in this
directory and issue, for example, "make ssdrv1". Then
execute using "ssdrv1".
