F02EKF Example Program Data
 10      : nx, matrix order n = nx*nx
 4       : nev, number of eigenvalues requested
 20      : ncv, size of subspace
 10.0    : rho, parameter for determining A
 5.5     : sigma, shift (want eigenvalues close to sigma)
 0       : print level
 500     : maximum number of itrerations
 1       : mode (0 = regular, 1 = shifted inverse)
 1       : imon (0 = no monitoring, 1 = monitoring on)