[gmx-users] question about adding two functions for one torsional angle

[David van der Spoel]

On 2011-04-18 21.46, Ming-Tsung Lee wrote:
> Dear all,
>
> I want to sum two functions for one torsional angle. Energy of the torsion
> (say, 1 2 3 4) is the combination of Ryckaert-Bellemans (function no.3)
> and compensated by periodic proper dihedral (function no.9). Is it
> possible that I simply type the follows, and GROMACS will add it up?
Yes.

>            func.  parameters
> 1 2 3 4   3      ...
> 1 2 3 4   9      ...
>
> I have search for the manual and articles, but I only found one possible
> option to scan the text file for the torsion. However, I was wondering
> whether there is a easy way to combined use two torsional functions for
> one torsion? Thank you.
The above way is the easy way.
>
> Best,
> Lee


-- 
David van der Spoel, Ph.D., Professor of Biology
Dept. of Cell & Molec. Biol., Uppsala University.
Box 596, 75124 Uppsala, Sweden. Phone:	+46184714205.
spoel at xray.bmc.uu.se    http://folding.bmc.uu.se