From: Josh Vermaas (vermaas2_at_illinois.edu)
Date: Thu May 26 2016 - 06:46:36 CDT

Hi Chitrak,

The first one would be the one I recommend, as its the loop form I tend
to use. It doesn't need the $sel delete statement to avoid leaking
memory, and doesn't depend on any default behavior for which frame gets
selected. The second loop could have something like:

set sel [atomselect top "?? condition ??" frame $i]

as well, which would technically make for shorter code, but in this case
it might be a useful way of double checking that the second loop variant
gives incorrect results.*

*-Josh*
*
On 05/25/2016 09:05 PM, Chitrak Gupta wrote:
> Oops, don't know how that happened. Thanks for pointing this out.
>
> So here is my question. What is the difference between the following
> two ways?
>
> ...
> set sel [atomselect top "?? condition ??"]
> for {set i 0} {$i < $nf} {incr i 1} {
> $sel frame $i
> $sel update
> ...
> }
>
> As opposed to
>
> ...
> for {set i 0} {$i < $nf} {incr i 1} {
> molinfo top set frame $i
> set sel [atomselect top "?? condition ??"]
> ...
> }
>
>
> I am trying to look for choline Nitrogens within a specific distance
> of aromatic side chains, and I am getting different results based on
> these two methods.
>
>
> Regards,
> Chitrak
>
> On Wed, May 25, 2016 at 10:52 PM, John Stone <johns_at_ks.uiuc.edu
> <mailto:johns_at_ks.uiuc.edu>> wrote:
>
> I'm afraid your email appears to have been truncated, and thus
> nobody will be able to answer your question.
>
> Cheers,
> John Stone
> vmd_at_ks.uiuc.edu <mailto:vmd_at_ks.uiuc.edu>
>
> On Wed, May 25, 2016 at 02:07:49PM -0400, Chitrak Gupta wrote:
> > Hello,
> >
> > I have this general question. When scripting in VMD, what is the
> difference
> > between the following two ways?
>
> --
> NIH Center for Macromolecular Modeling and Bioinformatics
> Beckman Institute for Advanced Science and Technology
> University of Illinois, 405 N. Mathews Ave, Urbana, IL 61801
> http://www.ks.uiuc.edu/~johns/
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