VMD-L Mailing List

From: Katherine Parra (kparra_at_mail.usf.edu)
Date: Tue Jul 22 2008 - 11:03:42 CDT

Dear VMD community:
*How do I correctly use the vecsub command to evaluate previously defined
variables?
*
This is part of my script:

set pta [atomselect top "index 1856"]
set ptb [atomselect top "index 1835"]
set ptc [atomselect top "index 724"]
set all [atomselect top all]

set acoor [lindex{$pta get {x y z}}0]
set bcoor [lindex{$ptb get {x y z}}0]

set absub [vecsub $bcoor $acoor]
set abmag [veclength $absub]

set ccoor [lindex{$ptc get {x y z}}0]

set acsub [vecsub $ccoor $acoor]
set acmag [veclength $acsub]

everytime I try to run this script I get an error message: *vecsub:
non-numeric in first argument

I was trying without using the lindex command first but then I read that
somebody else asked you about this and he used the lindex command and it
worked, but know I am using the lindex command and It is not working at all.
What could I do?

Thanks in advance.
KP
*