[gmx-users] How to compute covariance???
Semen Esilevsky
yesint4 at yahoo.com
Tue Jan 4 10:43:51 CET 2005
Dear gmx users,
I'm sorry for stupid question, but I can't find the
answer for two days :(
The problem is how to compute the correlation (or
covariance) of two particular atoms using the
MDtrajectory. I just need a correct equation for
this
(not the program, which does this).
If I have the atoms i and j I'd rather compute the
covariance between them as
cov_ij = <(xi-xi_mean)*(xj-xj_mean)> +
<(yi-yi_mean)*(yj-yj_mean)> +
<(zi-zi_mean)*(zj-zj_mean)>
But I'm confused about the "off-diagonal" averages
like
<(xi-xi_mean)*(zj-zj_mean)>. Do I have to include
them
or not and how?
Thank you in advance for help!
Semen
__________________________________
Do you Yahoo!?
Yahoo! Mail - You care about security. So do we.
http://promotions.yahoo.com/new_mail
More information about the gromacs.org_gmx-users
mailing list