The Eigenvector Following routine [7] is the default geometry
optimization method. For systems with more than 100 variables, the L-BFGS
optimizer is the default. To prevent the L-BFGS optimizer being used, add
keyword EF. That is, EF is provided to allow
explicit definition of the optimizer. Alternative geometry optimizers are
the BFGS [19,20,21,22] and the low-memory method,
L-BFGS . See also DDMAX,
DDMIN, DMAX, HESS, IUPD,
LET, MODE=, NONR, OMIN, PRNT=,
RECALC, RMAX, RMIN, RSCAL.
The current EF, while very reliable, is sometimes slow. To over-ride
some safety checks, specify LET. This will sometimes make the job run
faster.