VMD-L Mailing List

From: Josh Vermaas (vermaas2_at_illinois.edu)
Date: Tue Sep 23 2014 - 09:08:07 CDT

The negative sign. If you use charge "-0.7982", it'll work. John can
probably be more enlightening about the details of WHY this is the case
(I ran into this problem with negative resids, and I couldn't figure out
why this was a problem), but the negative sign screws up the
atomselection parser somehow unless its put in quotations. Note that
negative numbers are allowed as math operands, so if you wanted charge >
-0.8 and charge < -0.79, there the negative signs are handled correctly.

-Josh Vermaas
On 09/22/2014 09:25 PM, M Karim wrote:
> Hi,
>
> I have different atom types in the structure, and found the easiest
> way to select them by their charges. In the selection menu, I can
> easily select atom types with positive charges. However, atoms with
> negative charges are not selected and I get this error:
>
> /Unable to parse this atom selection./
>
>
> I, for example, use this command in the Selected Atoms area:
>
> *charge -0.798200*
>
> The command window also shows:
>
> /ERROR) syntax error/
>
>
> What is the problem with the syntax?
>
> Thank you.