From: Marzieh Alishahi (alishahi.mar_at_gmail.com)
Date: Mon Dec 24 2012 - 11:32:49 CST

Many thanks dear Caio!
It's a great hint!

Cheers

On Mon, Dec 24, 2012 at 8:47 PM, Caio S. Souza <caiobiounb_at_gmail.com> wrote:

> Hello,
> Using the "and" keyword, you're trying to select atoms that are
> "water" and "ion" at the same time. That's why it doesn't work.
> Try with set sel [atomselect top "water or ion" frame 0]
>
> Cheers
> --
> Caio S. Souza
> Laboratório de Biofísica Teórica e Computacional
> Universidade de Brasília
>
>
>
> 2012/12/24 Marzieh Alishahi <alishahi.mar_at_gmail.com>:
> > Dear VMD users
> >
> > I know it might be a simple question, but it would be a great aide if
> anyone
> > helps me. I want to write DAT file base my VEL.DCD file. Primarily I
> want to
> > compute the mean velocity of water and ion molecules at each time. But
> when
> > I want to select both water and ion in an atomselection command no atom
> were
> > selected, I used this comment;
> >
> >> set sel [atomselect top "water and ion" frame 0]
> >
> > atomselect8
> >
> >> $sel num
> >
> > 0
> >
> >> set sel [atomselect top "water" frame 0]
> >
> > atomselect7
> >
> >> $sel num
> >
> > 272049
> >
> >> sel [atomselect top "ion" frame 0]
> >
> > atomselect9
> >
> >> $sel num
> >
> > 3524
> >
> >
> >
> > I can select water and ion in two different selection group, but I want
> to
> > know if there is any way to have them both in one selection group?
> >
> > Any helps is highly appreciated
> >
> > Best
> >
> > Marzieh Alishahi
>