VMD-L Mailing List

From: Caio S. Souza (caiobiounb_at_gmail.com)
Date: Mon Dec 24 2012 - 11:17:24 CST

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