[Re: [Re: Regarding code modification]]

i want to calculate the angle between the particle and dihedral angle
every step.

Could you please tell us how do you calculate an angle between “a particle” and “a dihedral angle” ?? If you need help, you have to be clear as Axel often points to… on a side note, think about using LAMMPS as a library around your code.
HTH

Vikas