Re: skip frames with bigdcd

From: Axel Kohlmeyer (akohlmey_at_cmm.chem.upenn.edu)
Date: Fri Jun 26 2009 - 15:41:03 CDT

On Fri, 2009-06-26 at 16:15 -0400, Payel Das wrote:
> Hello all,

payel,

a few remarks before answering your question.

a) bigdcd is a VMD script, so your question is a VMD
   question. posting your question on the VMD mailing list
   would be more appropriate and has a higher chance
   to get a competent answer.

b) the address of the mailing list is namd-l_at_ks.uiuc.edu
   and _not_ owner-name-l_at_ks.uiuc.edu. the latter is the
   address of the mailing list maintainer.

> How can I skip every n frames while calculating certain quantities
> using bigdcd.tcl?

that depends.

the fastest way is:
you can try to modify the "animate read" command line in
the script to include the "skip" keyword. for details on
"animate" check out the VMD user's guide. you should note
that skip will be computed new for each file, so depending
on how many frames you have per file, it may not give a
perfectly evenly spaced analysis.

the careful way is:
write you callback function so that it checks the frame
number argument and process the data only if the timestep
is a multiple of n and otherwise just skip ahead.

cheers,
   axel.
>
> Thanks a lot,
>
> Payel Das
>

-- 
=======================================================================
Axel Kohlmeyer   akohlmey_at_cmm.chem.upenn.edu   http://www.cmm.upenn.edu
   Center for Molecular Modeling   --   University of Pennsylvania
Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323
tel: 1-215-898-1582,  fax: 1-215-573-6233,  office-tel: 1-215-898-5425
=======================================================================
If you make something idiot-proof, the universe creates a better idiot.

This archive was generated by hypermail 2.1.6 : Wed Feb 29 2012 - 15:51:07 CST