[lammps-users] Force constant matrix?

There are no 2nd derivatives in LAMMPS. I suppose
you could approx it by differencing, but there is no compute or
fix in LAMMPS currently that does that.


Trying writing a wrapper around the lammps. Calculate the energy using lammps, extract coordinate and energy information from lammps and then take taken second derivatives with respect to displacement (as you find appropriate) to calculate force matrix using finite difference approach.