Prev Up Next 

Keyword category:

Eigenvector Following

HESS

HESS — Specify the source of the Hessian matrix.

Usage

HESS=n

Description

This keyword indicates to the EF algorithm where to obtain its original Hessian matrix based on the value of n.
n=0 :

Use a diagonal matrix.
n=1 :

Calculate it numerically (single finite difference of the gradient) (default for TS).
n=2 :

(No longer used)
n=3 :

Calculate it numerically (central finite difference of the gradient).
n=4 :

Restart EF from a previous EF restart file, (jobname.res)
n=5 :

Compute a full Hessian using LTRD in either Cartesian or internal coordinates.
n=6 :

Fast estimate using 2-body model then refine low eigenmodes by Powell Rank 1 Update.
n=7 :

Fast estimate using 2-body model (default for EF).

Abbreviation:

none

Requires:

TS or EF

Required by:

none

Default value:

7 with EF; 1 with TS

See also:

EF, LTRD, TS, OMIN.
Prev  Up  Next
GRID  Home  HESSEI

Copyright © 1994, 1997, 2004, Semichem, Inc. All rights reserved.