VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Fri Nov 06 2015 - 00:09:36 CST

JC,
  You can set/get velocity components just like coordinates, like this:

set sel [atomselect top all]
$sel get { vx vy vz }
$sel set vx 1.0
$sel get { vx vy vz }

As more trajectory formats add explicit support for velocity or other
info, we'll continue to add them into VMD and the molfile plugins.

Cheers,
  John Stone
  vmd_at_ks.uiuc.edu

On Fri, Nov 06, 2015 at 05:43:12AM +0000, JC Gumbart wrote:
> Is there a way to access it using TCL commands though?A Or do we need c
> code?
>
> Thanks!
> JC
>
> On Thu, Nov 5, 2015, 9:51 PMA JC Gumbart <[1]gumbart_at_physics.gatech.edu>
> wrote:
>
> Hi John et al.,
>
> We have a problem where we would like to store velocity data for a
> molecule.A However, it seems this array only gets initialized if the
> filetype already contains such data.A This is what I see in
> MolFilePlugin.C
>
> >A A // allocate space for velocities only if
> >A A // 1) the plugin implements read_timestep_metadata;
> >A A // 2) metadata->has_velocities is TRUE.
> >A A float *velocities = NULL;
>
> Is there any way around that?A Wea**d rather not have to use TCL lists
> to store the data (too slow).
>
> Thanks!
> JC
>
> References
>
> Visible links
> 1. mailto:gumbart_at_physics.gatech.edu 

-- 
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/           Phone: 217-244-3349
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