From: Axel Kohlmeyer (akohlmey_at_gmail.com)
Date: Mon May 24 2010 - 07:41:35 CDT
On Mon, May 24, 2010 at 7:48 AM, Jun Zhang <coolrainbow_at_yahoo.cn> wrote:
> Hi everyone:
>
> I have one basic question about essential dynamics. It is well known that PCA performs such a calculation:
>
> <(x-<x>)T (x-<x>)> = P lamda PT (where XT denotes the transpose of matrix X)
>
> My question is , assume the coordination vector x(t), eigenvalue lambda1 and corresponding eigenvector P1,
>
> 1. what does it mean when we refer to "projection of the trajectory onto eigenvector P1", I think it is x(t)T*P1 (scalar production), is it true?
>
> 2. what does it mean when we refer to "projection of the structure onto eigenvector P1", which results a new structure? Can anyone give an explicit formula?
please have a lookat:
Biophysical Journal, Volume 86, Issue 3, 1393-1407, 1 March 2004
http://dx.doi.org/10.1016/S0006-3495(04)74210-1
it has a comprehensive discussion of the issues that you are
inquiring about and a usage example.
cheers,
axel.
> Thank you for your help!
>
> Jun Zhang
> Nankai University
> coolrainbow_at_yahoo.cn
>
>
>
>
>
-- Dr. Axel Kohlmeyer akohlmey_at_gmail.com http://sites.google.com/site/akohlmey/ Institute for Computational Molecular Science Temple University, Philadelphia PA, USA.
This archive was generated by hypermail 2.1.6 : Wed Feb 29 2012 - 15:55:48 CST