From: Ali Khanlarkhani (alikhanlarkhani_at_yahoo.com)
Date: Sun Sep 30 2012 - 12:32:29 CDT
Dear Chris
Many thanks, really helpful, in my idea your following sentence,
should be added to 'ParseFEP Plugin' manual:
"The farthest you are from second-order perturbation theory, the slower the
convergence of your Gram-Charlier expansion."
regards
Ali
________________________________
From: Chris Chipot <chipot_at_ks.uiuc.edu>
To: Ali Khanlarkhani <alikhanlarkhani_at_yahoo.com>
Cc: "namd-l_at_ks.uiuc.edu" <namd-l_at_ks.uiuc.edu>
Sent: Sunday, September 30, 2012 8:16 PM
Subject: Re: namd-l: Convergence of the Gram-Charlier expansion
Khanlarkhani,
you can restate your free energy change,
as
where g(∆U) is a Gaussian distribution and Hn(∆U) are Hermite polynomials.
The farthest you are from second-order perturbation theory, the
slower the
convergence of your Gram-Charlier expansion.
As for the order, it is pretty much system dependent. Charging a
van der
Waals particle will evidently be pretty quick.
Chris Chipot
On 9/30/12 5:34 PM, Ali Khanlarkhani wrote:
The following sentence come from "ParseFEP Plugin, Version 1.5" manual:
>
>"Convergence of the Gram-Charlier expansion at a given order represents a relevant measure of how well-defined the probability distribution is."
>What does it mean? convergence at what order is good?
>
>Khanlarkhani
>
--
_______________________________________________________________________ Chris Chipot, Ph.D.
Theoretical and Computational Biophysics Group
Beckman Institute
University of Illinois at Urbana-Champaign
405 North Mathews Phone: (217) 244-5711
Urbana, Illinois 61801 Fax: (217) 244-6078 E-mail: chipot_at_ks.uiuc.edu Christophe.Chipot_at_edam.uhp-nancy.fr Web: http://www.ks.uiuc.edu/~chipot http://www.edam.uhp-nancy.fr The light shines in the darkness, and the darkness has not overcome it. John 1:5.
_______________________________________________________________________
This archive was generated by hypermail 2.1.6 : Tue Dec 31 2013 - 23:22:38 CST