mstk.forcefield.Ppf

class mstk.forcefield.Ppf(file)

Parse ForceField from PPF file.

PPF is the native format of Direct Force Field. Currently, only the DFF-AMBER functional form of PPF is supported, which contains following terms:

In PPF file, there is no leading 1/2 for harmonic energy terms. The length is in unit of Angstrom, and angle is in unit of degree. The energies for bond, angle and vdW are in unit of kcal/mol/A^2, kcal/mol/rad^2 and kcal/mol. The two values for LJ interaction are r_min and epsilon.

PPF format can optionally store the version of parameters. If a force field term describing one topology element appear several times, only the one with the latest version will be loaded. If there are duplicated terms without version record, an Exception will be raised.

Parameters:

file (str) –

forcefield
Type:

ForceField

Methods

__init__(file)