1. Purpose ------- This directory contains example drivers that call ARPACK subroutines [c,z]naupd.f and [c,z]neupd.f to solve COMPLEX eigenvalue problems using regular, inverse or shift-invert modes. 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 'XndrvN.f', where X - is 'c' (single precision complex) or 'z' (double precision complex) N - is a number between 1 and 4. 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. For shift-invert modes (N=2,4), the user needs to provide a complex linear system solver to perform y=inv[A-sigma*B]*x. 3. Usage ----- To run these drivers, you may use the makefile in this directory and issue, for example, "make cndrv1". Then execute using "cndrv1".