mstk.ommhelper.force.spring_self¶

mstk.ommhelper.force.spring_self(system, positions, particles, strength)¶

Restrain the selected particles at their original positions.

Note that the original positions will NOT change with box size if there is a barostat.

Parameters:

system (mm.System) – The OpenMM system to be simulated
positions (array_like) – The positions of all particles in the system in unit of nm
particles (list of int) – The indexes of particles to be restrained
strength (list of float) – The strength of harmonic restraint in x, y and z directions. Three elements should be provided in unit of kJ/mol/nm^2

Returns:

force

Return type:

mm.CustomExternalForce

mstk