11.5. Bond, angle, dihedral, improper styles

Classes that compute molecular interactions are derived from the Bond, Angle, Dihedral, and Improper classes. New styles can be created to add new potentials to LAMMPS.

Bond_harmonic.cpp is the simplest example of a bond style. Ditto for the harmonic forms of the angle, dihedral, and improper style commands.

Here is a brief description of common methods you define in your new derived class. See bond.h, angle.h, dihedral.h, and improper.h for details and specific additional methods.

init check if all coefficients are set, calls init_style (optional)
init_style check if style specific conditions are met (optional)
compute compute the molecular interactions (required)
settings apply global settings for all types (optional)
coeff set coefficients for one type (required)
equilibrium_distance length of bond, used by SHAKE (required, bond only)
equilibrium_angle opening of angle, used by SHAKE (required, angle only)
write & read_restart writes/reads coeffs to restart files (required)
single force and energy of a single bond or angle (required, bond or angle only)
memory_usage tally memory allocated by the style (optional)