[CPMD-list] RMS gradient

[Juerg Hutter]

Hi

The root mean square
(see http://mathworld.wolfram.com/Root-Mean-Square.html)
is a measure for the size of a distribution. We use it
to give a size of the electronic gradient during the
minimization. The optimized energy is found for
the case of zero gradient. Numerically this is monitored
by the RMS value of the gradient.
However, there is a second measure, the largest absolute
value of an element of the gradient.
In CPMD both measures are printed, side by side in the
output. Convergence is checked wrt the largest gradient
element. Convergence is assumed if this value
falls below a threshold (default 10^-5).

regards

Juerg Hutter

----------------------------------------------------------
Juerg Hutter                   Phone : ++41 1 635 4491
Physical Chemistry Institute   FAX   : ++41 1 635 6838
University of Zurich           E-mail: hutter at pci.unizh.ch
Winterthurerstrasse 190
CH-8057 Zurich, Switzerland
----------------------------------------------------------


On Tue, 25 Jan 2005, Keta Jones wrote:

> Please help me to explain the significance of "Root
> mean square gradient" for energy minimization of
> systems.How can I check this from CPMD output file ?
>
> regards
> keta
>
> =====
> Keta
> **************************************************************************************
>
>
>
>
> __________________________________
> Do you Yahoo!?
> Yahoo! Mail - You care about security. So do we.
> http://promotions.yahoo.com/new_mail
> _______________________________________________
> CPMD-list mailing list
> CPMD-list at cpmd.org
> http://cpmd.org/mailman/listinfo/cpmd-list
>