I am using a May, 21, 2008 version LAMMPS.
I want to minimize the energy of a group of atoms. I set the ftol, maxiter and maxeval (which are parameters for minimize command) to a reasonable value. But the result of the model after relaxation shows that there are forces about 1e-5eV/A in x, y and z direction for most atoms. However, the force on atoms after relaxation should be about zero. I want the residual force to be less than 1e-9ev/A. How can I reduce the error of force?