Re: [ESPResSo-users] Gamma_rot for individual particle

[Rudolf Weeber]

Hi,
On Tue, Nov 14, 2017 at 12:37:42AM +0530, Nairhita Samanta wrote:
> I wanted to know how can I set different gamma_rot for different particle
> in a system. I am getting this following error "unknown particle parameter
> "gamma_rot"" if I try to set different gamma_rot for different particle.
> 
> And do I need to first define Langevin thermostat by "thermostat langevin
> 1.0 3.0 1.0 on on" and then change gamma and gamma rot for each particle
> later on. When rotation is compiled, is it compile for every particle or
> can I selectively choose particle for some of which the rotation is not
> integrated.
First of all, based on the code fragments, I assume you are using the TCL 
version of Espresso.
Please note that we do not support this version any longer. I strongly suggest, 
you base any new scripts on the Python-based Espresso at
http://github.com/espressomd/espresso
In particular, the rotation and Langeivn per particle features are much better 
supported (and tested) in the Python-based version.

Regarding your questions:
For the TCL version, you probably need
#define ROTATION
#define ROTATION_PER_PARTICLE
#define LANGEVIN_PER_PARTICLE
#define ROTATIONAL_INERTIA
in your myconfig.hpp. Also, your chances are best with the latest version of 
the tcl branch from above github url.
For docs on ROTATION_PER_PARTICLE see the "rotation" particle property in the 
user's guide.

The rotational gamma set in the Langevin thermostat is used whenever no 
particle-specific values are provided.

Hope that helps!
Regards, Rudolf