The two files dnaupc and dneupc are needed to use the 
Cayley transformation mode with ARPACK. They replace
dnaupd and dneupd, respectively. The user can use template
driver dndrv4.f as a guide. Details of how to use the
Cayley transformation mode for linear stability analysis
are given in "Implicitly restarted Arnoldi methods and
eigenvalues of the discretized Navier Stokes equations"
by R.B. Lehoucq and J.A. Scott. Contact either author
for a copy (rlehoucq@cs.sandia.gov, J.Scott@letterbox.rl.ac.uk).