from typing import Callable, ClassVar, Optional, Tuple
from pydantic import Field
from gmso.abc.abstract_connection import Connection
from gmso.core.atom import Atom
from gmso.core.dihedral_type import DihedralType
[docs]class Dihedral(Connection):
__base_doc__ = """A 4-partner connection between sites.
This is a subclass of the gmso.Connection superclass.
This class has strictly 4 members in its connection_members.
The connection_type in this class corresponds to gmso.DihedralType.
The connectivity of a dihedral is:
m1–m2–m3–m4
where m1, m2, m3, and m4 are connection members 1-4, respectively.
Notes
-----
Inherits some methods from Connection:
__eq__, __repr__, _validate methods
Additional _validate methods are presented
"""
__members_creator__: ClassVar[Callable] = Atom.parse_obj
connection_members_: Tuple[Atom, Atom, Atom, Atom] = Field(
..., description="The 4 atoms involved in the dihedral."
)
dihedral_type_: Optional[DihedralType] = Field(
default=None, description="DihedralType of this dihedral."
)
@property
def dihedral_type(self):
return self.__dict__.get("dihedral_type_")
@property
def connection_type(self):
# ToDo: Deprecate this?
return self.__dict__.get("dihedral_type_")
[docs] def equivalent_members(self):
"""Get a set of the equivalent connection member tuples
Returns
_______
frozenset
A unique set of tuples of equivalent connection members
Notes
_____
For a dihedral:
i, j, k, l == l, k, j, i
where i, j, k, and l are the connection members.
"""
return frozenset(
[self.connection_members, tuple(reversed(self.connection_members))]
)
def _equivalent_members_hash(self):
"""Returns a unique hash representing the connection
Returns
_______
int
A unique hash to represent the connection members
Notes
_____
For a dihedral:
i, j, k, l == l, k, j, i
where i, j, k, and l are the connection members.
Here i and j are interchangeable, j and k are interchangeable,
and k and l are interchangeble, as long as each are adjacent to
one another.
"""
return hash(
frozenset(
[
frozenset(
[self.connection_members[0], self.connection_members[1]]
),
frozenset(
[self.connection_members[1], self.connection_members[2]]
),
frozenset(
[self.connection_members[2], self.connection_members[3]]
),
]
)
)
def __setattr__(self, key, value):
if key == "connection_type":
super(Dihedral, self).__setattr__("dihedral_type", value)
else:
super(Dihedral, self).__setattr__(key, value)
[docs] class Config:
fields = {
"dihedral_type_": "dihedral_type",
"connection_members_": "connection_members",
}
alias_to_fields = {
"dihedral_type": "dihedral_type_",
"connection_members": "connection_members_",
}