from typing import Tuple, Optional
import unyt as u
from pydantic import Field
from gmso.core.parametric_potential import ParametricPotential
from gmso.utils._constants import DIHEDRAL_TYPE_DICT
[docs]class DihedralType(ParametricPotential):
__base_doc__ = """A descripton of the interaction between 4 bonded partners.
This is a subclass of the gmso.core.Potential superclass.
DihedralType represents a dihedral type and includes the functional form
describing its interactions. The functional form of the potential is stored
as a `sympy` expression and the parameters, with units, are stored
explicitly. The AtomTypes that are used to define the dihedral type are
stored as `member_types`.
The connectivity of a dihedral is:
m1–m2–m3–m4
where m1, m2, m3, and m4 are connection members 1-4, respectively.
Notes
----
Inherits many functions from gmso.ParametricPotential:
__eq__, _validate functions
"""
member_types_: Optional[Tuple[str, str, str, str]] = Field(
None,
description='List-like of of gmso.AtomType.name or gmso.AtomType.atomclass '
'defining the members of this dihedral type'
)
def __init__(self,
name='DihedralType',
expression='k * (1 + cos(n * phi - phi_eq))**2',
parameters=None,
independent_variables=None,
member_types=None,
topology=None,
tags=None):
if parameters is None:
parameters = {
'k': 1000 * u.Unit('kJ / (deg**2)'),
'phi_eq': 180 * u.deg,
'n': 1 * u.dimensionless
}
if independent_variables is None:
independent_variables = {'phi'}
super(DihedralType, self).__init__(
name=name,
expression=expression,
parameters=parameters,
independent_variables=independent_variables,
topology=topology,
member_types=member_types,
set_ref=DIHEDRAL_TYPE_DICT,
tags=tags
)
@property
def member_types(self):
return self.__dict__.get('member_types_')
class Config:
fields = {
'member_types_': 'member_types'
}
alias_to_fields = {
'member_types': 'member_types_'
}