forcefield.py

"""
 Manage Forcefield parameters (vdw, Srf)
 uses modified CMIP vdwprm file
"""
import sys

class VdwParamset():
    def __init__(self, file_name):
        self.at_types = {}
        try:
            fh = open(file_name, "r")
        except OSError:
            print("#ERROR while loading parameter file (", file_name, ")")
            sys.exit(2)
        for line in fh:
            if line[0] == '#':
                continue
            data = line.split()
            self.at_types[data[0]] = AtomType(data)
        self.ntypes = len(self.at_types)
        fh.close()

class AtomType():
    def __init__(self, data):
        self.id   = data[0]
        self.eps  = float(data[1])
        self.sig  = float(data[2])
        self.mass = float(data[3])
        self.fsrf = float(data[4])
        self.rvdw = self.sig * 0.5612