Is there constraint forces contribute in what I am saving in the .trr format?

User discussions
1

GROMACS version: 2020
GROMACS modification: No

Hi everyone,
When I use some holonomic constraints on my atoms (eg. SHAKE or LINCS), the total force is given by the gradient of the potential-energy plus a contribute of constraint forces fixed by lagrangian multipliers and the expression of the constraint. When I am saving forces for each single atom in the mdp option, am I saving the total force or only one of these contributes?

Thanks for the help.

Francesco

2

The forces saved in the trr file contain only the gradient of the potential, no constraint contributions.