[gmx-users] Write force on a single particle

[simon.grosse-holz at fau.de]

Dear All,

is it possible to write the forces of only one (type of) particle to the 
trajectory?

I am using GROMACS to simulate the dispersion of a hydrophobic particle 
in a big box of water and am interested in the force acting on the 
particle. Simply writing all the forces to the trajectory (via nstfout) 
also writes all the forces on the water molecules, which is a lot of 
data that actually I do not need. For the compressed trajectory output I 
can specify the groups to write, which would perfectly solve my problem, 
if the compressed trajectories could hold forces. That, however, is not 
the case (as far as I know; is that correct?). So is there any other way 
to get only the force acting on the one particle?

Thanks,
Simon