HP MLIB User's Guide Vol. 2 7th Ed.

Chapter 15 Sparse Eigenvalues and Eigenvectors 1037
Eigenextraction DSEVEX
’H’ or ’h’ The highest (greatest magnitude)
eigenvalues.
’C’ or ’c’ or
’N’ or ’n’ The eigenvalues nearest center.
’A’ or ’a’ All eigenvalues in the specified
interval.
pbtype Character string indicating type of problem:
’V’ or ’v’ Generalized symmetric (vibration)
problem Kx = λMx, with M positive
semi definite.
’B’ or ’b’ Generalized symmetric (buckling)
problem Kx = λK
δ
x, with K positive
semi definite and K
δ
possibly
indefinite.
’O’ or ’o’ Ordinary symmetric eigenproblem
Kx = λx.
lfinit If .TRUE., the value of the argument lftend is to be
used as a restriction on the location of computed
eigenvalues. If .FALSE., no lower bound is placed on
the value of computed eigenvalues; equivalently, the
left endpoint is negative infinity.
lftend Left endpoint of an interval in which the desired
eigenvalues lie; not used if lfinit is .FALSE.
rfinit If .TRUE., the value of the argument rhtend is to be
used as a restriction on the location of computed
eigenvalues. If .FALSE., no upper bound is placed on
the value of computed eigenvalues; equivalently, the
right endpoint is positive infinity.
rhtend Right endpoint of an interval in which the desired
eigenvalues lie; not used if rfinit is .FALSE.
center A center or critical value for use when eigenvalues
nearest some particular value are desired. Referenced
only when which specifies ’centered’ or ’nearest’.
mxbksz A limit on the block size used in the block Lanczos
recurrence. In general, it is best to choose a block size
as large as, or slightly larger than, the largest
multiplicity of the eigenvalues desired. The following
constraints also apply: