[lammps-users] setforce 0.0 0.0 0.0 But yes it is moving

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1

Hi all ,

i have a rigid construction and some molecules around it. The first thing i did was to minimize my system and then running my simulation keeping the rigid body still with :
fix 1 my_const single
fix 2 my_const setforce 0.0 0.0 0.0

After i wanted to see what’s going on i i wouldn’t use the minimization. So i tried to do the same data file in the same file with the simulation. All of a sudden i see that my construction is moving.Why is this happening?

Jim

2

Did you make sure about the initial velocities? Are they set to zero as well?

3

Yes i have set velocities only for the other molecules.for my_const i put either zero or nothing,but the same result…

4

If you're running dynamics, atoms won't move unless you
integrate them. Or you run NPT and the box size
changes dilate them (which can be turned off with
the fix npt) command.

For minimization, atoms won't move if you set the
force on them to 0.

Steve