# coding: utf-8
# Copyright (c) Pymatgen Development Team.
# Distributed under the terms of the MIT License.
from __future__ import division, print_function, unicode_literals, \
absolute_import
from collections import OrderedDict
from io import StringIO
import itertools
import re
import warnings
import numpy as np
import pandas as pd
from monty.json import MSONable
from monty.dev import deprecated
from ruamel.yaml import YAML
from six import string_types
from pymatgen.util.io_utils import clean_lines
from pymatgen import Molecule, Element, Lattice, Structure, SymmOp
"""
This module implements a core class LammpsData for generating/parsing
LAMMPS data file, and other bridging classes to build LammpsData from
molecules.
Only point particle styles are supported for now (atom_style in angle,
atomic, bond, charge, full and molecular only). See the pages below for
more info.
http://lammps.sandia.gov/doc/atom_style.html
http://lammps.sandia.gov/doc/read_data.html
"""
__author__ = "Kiran Mathew, Zhi Deng"
__copyright__ = "Copyright 2018, The Materials Virtual Lab"
__version__ = "1.0"
__maintainer__ = "Zhi Deng"
__email__ = "z4deng@eng.ucsd.edu"
__date__ = "Aug 1, 2018"
SECTION_KEYWORDS = {"atom": ["Atoms", "Velocities", "Masses",
"Ellipsoids", "Lines", "Triangles", "Bodies"],
"topology": ["Bonds", "Angles", "Dihedrals", "Impropers"],
"ff": ["Pair Coeffs", "PairIJ Coeffs", "Bond Coeffs",
"Angle Coeffs", "Dihedral Coeffs",
"Improper Coeffs"],
"class2": ["BondBond Coeffs", "BondAngle Coeffs",
"MiddleBondTorsion Coeffs",
"EndBondTorsion Coeffs", "AngleTorsion Coeffs",
"AngleAngleTorsion Coeffs",
"BondBond13 Coeffs", "AngleAngle Coeffs"]}
CLASS2_KEYWORDS = {"Angle Coeffs": ["BondBond Coeffs", "BondAngle Coeffs"],
"Dihedral Coeffs": ["MiddleBondTorsion Coeffs",
"EndBondTorsion Coeffs",
"AngleTorsion Coeffs",
"AngleAngleTorsion Coeffs",
"BondBond13 Coeffs"],
"Improper Coeffs": ["AngleAngle Coeffs"]}
SECTION_HEADERS = {"Masses": ["mass"],
"Velocities": ["vx", "vy", "vz"],
"Bonds": ["type", "atom1", "atom2"],
"Angles": ["type", "atom1", "atom2", "atom3"],
"Dihedrals": ["type", "atom1", "atom2", "atom3", "atom4"],
"Impropers": ["type", "atom1", "atom2", "atom3", "atom4"]}
ATOMS_HEADERS = {"angle": ["molecule-ID", "type", "x", "y", "z"],
"atomic": ["type", "x", "y", "z"],
"bond": ["molecule-ID", "type", "x", "y", "z"],
"charge": ["type", "q", "x", "y", "z"],
"full": ["molecule-ID", "type", "q", "x", "y", "z"],
"molecular": ["molecule-ID", "type", "x", "y", "z"]}
[docs]class LammpsBox(MSONable):
"""
Object for representing a simulation box in LAMMPS settings.
"""
def __init__(self, bounds, tilt=None):
"""
Args:
bounds: A (3, 2) array/list of floats setting the
boundaries of simulation box.
tilt: A (3,) array/list of floats setting the tilt of
simulation box. Default to None, i.e., use an
orthogonal box.
"""
bounds_arr = np.array(bounds)
assert bounds_arr.shape == (3, 2), \
"Expecting a (3, 2) array for bounds," \
" got {}".format(bounds_arr.shape)
self.bounds = bounds_arr.tolist()
matrix = np.diag(bounds_arr[:, 1] - bounds_arr[:, 0])
self.tilt = None
if tilt is not None:
tilt_arr = np.array(tilt)
assert tilt_arr.shape == (3,),\
"Expecting a (3,) array for box_tilt," \
" got {}".format(tilt_arr.shape)
self.tilt = tilt_arr.tolist()
matrix[1, 0] = tilt_arr[0]
matrix[2, 0] = tilt_arr[1]
matrix[2, 1] = tilt_arr[2]
self._matrix = matrix
def __str__(self):
return self.get_string()
def __repr__(self):
return self.get_string()
@property
def volume(self):
"""
Volume of simulation box.
"""
m = self._matrix
return np.dot(np.cross(m[0], m[1]), m[2])
[docs] def get_string(self, significant_figures=6):
"""
Returns the string representation of simulation box in LAMMPS
data file format.
Args:
significant_figures (int): No. of significant figures to
output for box settings. Default to 6.
Returns:
String representation
"""
ph = "{:.%df}" % significant_figures
lines = []
for bound, d in zip(self.bounds, "xyz"):
fillers = bound + [d] * 2
bound_format = " ".join([ph] * 2 + [" {}lo {}hi"])
lines.append(bound_format.format(*fillers))
if self.tilt:
tilt_format = " ".join([ph] * 3 + [" xy xz yz"])
lines.append(tilt_format.format(*self.tilt))
return "\n".join(lines)
[docs] def get_box_shift(self, i):
"""
Calculates the coordinate shift due to PBC.
Args:
i: A (n, 3) integer array containing the labels for box
images of n entries.
Returns:
Coorindate shift array with the same shape of i
"""
return np.inner(i, self._matrix.T)
[docs] def to_lattice(self):
"""
Converts the simulation box to a more powerful Lattice backend.
Note that Lattice is always periodic in 3D space while a
simulation box is not necessarily periodic in all dimensions.
Returns:
Lattice
"""
return Lattice(self._matrix)
[docs]def lattice_2_lmpbox(lattice, origin=(0, 0, 0)):
"""
Converts a lattice object to LammpsBox, and calculates the symmetry
operation used.
Args:
lattice (Lattice): Input lattice.
origin: A (3,) array/list of floats setting lower bounds of
simulation box. Default to (0, 0, 0).
Returns:
LammpsBox, SymmOp
"""
a, b, c = lattice.abc
xlo, ylo, zlo = origin
xhi = a + xlo
if lattice.is_orthogonal:
yhi = b + ylo
zhi = c + zlo
tilt = None
rot_matrix = np.eye(3)
else:
m = lattice.matrix
xy = np.dot(m[1], m[0] / a)
yhi = np.sqrt(b ** 2 - xy ** 2) + ylo
xz = np.dot(m[2], m[0] / a)
yz = (np.dot(m[1], m[2]) - xy * xz) / (yhi - ylo)
zhi = np.sqrt(c ** 2 - xz ** 2 - yz ** 2) + zlo
tilt = [xy, xz, yz]
rot_matrix = np.linalg.solve([[xhi - xlo, 0, 0],
[xy, yhi - ylo, 0],
[xz, yz, zhi - zlo]], m)
bounds = [[xlo, xhi], [ylo, yhi], [zlo, zhi]]
symmop = SymmOp.from_rotation_and_translation(rot_matrix, origin)
return LammpsBox(bounds, tilt), symmop
[docs]class LammpsData(MSONable):
"""
Object for representing the data in a LAMMPS data file.
"""
def __init__(self, box, masses, atoms, velocities=None, force_field=None,
topology=None, atom_style="full"):
"""
This is a low level constructor designed to work with parsed
data or other bridging objects (ForceField and Topology). Not
recommended to use directly.
Args:
box (LammpsBox): Simulation box.
masses (pandas.DataFrame): DataFrame with one column
["mass"] for Masses section.
atoms (pandas.DataFrame): DataFrame with multiple columns
for Atoms section. Column names vary with atom_style.
velocities (pandas.DataFrame): DataFrame with three columns
["vx", "vy", "vz"] for Velocities section. Optional
with default to None. If not None, its index should be
consistent with atoms.
force_field (dict): Data for force field sections. Optional
with default to None. Only keywords in force field and
class 2 force field are valid keys, and each value is a
DataFrame.
topology (dict): Data for topology sections. Optional with
default to None. Only keywords in topology are valid
keys, and each value is a DataFrame.
atom_style (str): Output atom_style. Default to "full".
"""
if velocities is not None:
assert len(velocities) == len(atoms),\
"Inconsistency found between atoms and velocities"
if force_field:
all_ff_kws = SECTION_KEYWORDS["ff"] + SECTION_KEYWORDS["class2"]
force_field = {k: v for k, v in force_field.items()
if k in all_ff_kws}
if topology:
topology = {k: v for k, v in topology.items()
if k in SECTION_KEYWORDS["topology"]}
self.box = box
self.masses = masses
self.atoms = atoms
self.velocities = velocities
self.force_field = force_field
self.topology = topology
self.atom_style = atom_style
def __str__(self):
return self.get_string()
def __repr__(self):
return self.get_string()
@property
def structure(self):
"""
Exports a periodic structure object representing the simulation
box.
Return:
Structure
"""
masses = self.masses
atoms = self.atoms.copy()
if "nx" in atoms.columns:
atoms.drop(["nx", "ny", "nz"], axis=1, inplace=True)
atoms["molecule-ID"] = 1
ld_copy = self.__class__(self.box, masses, atoms)
topologies = ld_copy.disassemble()[-1]
molecule = topologies[0].sites
coords = molecule.cart_coords - np.array(self.box.bounds)[:, 0]
species = molecule.species
latt = self.box.to_lattice()
site_properties = {}
if "q" in atoms:
site_properties["charge"] = atoms["q"].values
if self.velocities is not None:
site_properties["velocities"] = self.velocities.values
return Structure(latt, species, coords, coords_are_cartesian=True,
site_properties=site_properties)
[docs] def get_string(self, distance=6, velocity=8, charge=3):
"""
Returns the string representation of LammpsData, essentially
the string to be written to a file.
Args:
distance (int): No. of significant figures to output for
box settings (bounds and tilt) and atomic coordinates.
Default to 6.
velocity (int): No. of significant figures to output for
velocities. Default to 8.
charge (int): No. of significant figures to output for
charges. Default to 3.
Returns:
String representation
"""
file_template = """Generated by pymatgen.io.lammps.data.LammpsData
{stats}
{box}
{body}
"""
box = self.box.get_string(distance)
body_dict = OrderedDict()
body_dict["Masses"] = self.masses
types = OrderedDict()
types["atom"] = len(self.masses)
if self.force_field:
all_ff_kws = SECTION_KEYWORDS["ff"] + SECTION_KEYWORDS["class2"]
ff_kws = [k for k in all_ff_kws if k in self.force_field]
for kw in ff_kws:
body_dict[kw] = self.force_field[kw]
if kw in SECTION_KEYWORDS["ff"][2:]:
types[kw.lower()[:-7]] = len(self.force_field[kw])
body_dict["Atoms"] = self.atoms
counts = OrderedDict()
counts["atoms"] = len(self.atoms)
if self.velocities is not None:
body_dict["Velocities"] = self.velocities
if self.topology:
for kw in SECTION_KEYWORDS["topology"]:
if kw in self.topology:
body_dict[kw] = self.topology[kw]
counts[kw.lower()] = len(self.topology[kw])
all_stats = list(counts.values()) + list(types.values())
stats_template = "{:>%d} {}" % len(str(max(all_stats)))
count_lines = [stats_template.format(v, k) for k, v in counts.items()]
type_lines = [stats_template.format(v, k + " types")
for k, v in types.items()]
stats = "\n".join(count_lines + [""] + type_lines)
map_coords = lambda q: ("{:.%df}" % distance).format(q)
map_velos = lambda q: ("{:.%df}" % velocity).format(q)
map_charges = lambda q: ("{:.%df}" % charge).format(q)
formatters = {"x": map_coords, "y": map_coords, "z": map_coords,
"vx": map_velos, "vy": map_velos, "vz": map_velos,
"q": map_charges}
section_template = "{kw}\n\n{df}\n"
parts = []
for k, v in body_dict.items():
index = True if k != "PairIJ Coeffs" else False
df_string = v.to_string(header=False, formatters=formatters,
index_names=False, index=index)
parts.append(section_template.format(kw=k, df=df_string))
body = "\n".join(parts)
return file_template.format(stats=stats, box=box, body=body)
[docs] def write_file(self, filename, distance=6, velocity=8, charge=3):
"""
Writes LammpsData to file.
Args:
filename (str): Filename.
distance (int): No. of significant figures to output for
box settings (bounds and tilt) and atomic coordinates.
Default to 6.
velocity (int): No. of significant figures to output for
velocities. Default to 8.
charge (int): No. of significant figures to output for
charges. Default to 3.
"""
with open(filename, "w") as f:
f.write(self.get_string(distance=distance, velocity=velocity,
charge=charge))
[docs] def disassemble(self, atom_labels=None, guess_element=True,
ff_label="ff_map"):
"""
Breaks down LammpsData to building blocks
(LammpsBox, ForceField and a series of Topology).
RESTRICTIONS APPLIED:
1. No complex force field defined not just on atom
types, where the same type or equivalent types of topology
may have more than one set of coefficients.
2. No intermolecular topologies (with atoms from different
molecule-ID) since a Topology object includes data for ONE
molecule or structure only.
Args:
atom_labels ([str]): List of strings (must be different
from one another) for labelling each atom type found in
Masses section. Default to None, where the labels are
automaticaly added based on either element guess or
dummy specie assignment.
guess_element (bool): Whether to guess the element based on
its atomic mass. Default to True, otherwise dummy
species "Qa", "Qb", ... will be assigned to various
atom types. The guessed or assigned elements will be
reflected on atom labels if atom_labels is None, as
well as on the species of molecule in each Topology.
ff_label (str): Site property key for labeling atoms of
different types. Default to "ff_map".
Returns:
LammpsBox, ForceField, [Topology]
"""
atoms_df = self.atoms.copy()
if "nx" in atoms_df.columns:
atoms_df[["x", "y", "z"]] += \
self.box.get_box_shift(atoms_df[["nx", "ny", "nz"]].values)
atoms_df = pd.concat([atoms_df, self.velocities], axis=1)
mids = atoms_df.get("molecule-ID")
if mids is None:
unique_mids = [1]
data_by_mols = {1: {"Atoms": atoms_df}}
else:
unique_mids = np.unique(mids)
data_by_mols = {}
for k in unique_mids:
df = atoms_df[atoms_df["molecule-ID"] == k]
data_by_mols[k] = {"Atoms": df}
masses = self.masses.copy()
masses["label"] = atom_labels
unique_masses = np.unique(masses["mass"])
if guess_element:
ref_masses = [el.atomic_mass.real for el in Element]
diff = np.abs(np.array(ref_masses) - unique_masses[:, None])
atomic_numbers = np.argmin(diff, axis=1) + 1
symbols = [Element.from_Z(an).symbol for an in atomic_numbers]
else:
symbols = ["Q%s" % a for a in
map(chr, range(97, 97 + len(unique_masses)))]
for um, s in zip(unique_masses, symbols):
masses.loc[masses["mass"] == um, "element"] = s
if atom_labels is None: # add unique labels based on elements
for el, vc in masses["element"].value_counts().iteritems():
masses.loc[masses["element"] == el, "label"] = \
["%s%d" % (el, c) for c in range(1, vc + 1)]
assert masses["label"].nunique(dropna=False) == len(masses), \
"Expecting unique atom label for each type"
mass_info = [tuple([r["label"], r["mass"]])
for _, r in masses.iterrows()]
nonbond_coeffs, topo_coeffs = None, None
if self.force_field:
if "PairIJ Coeffs" in self.force_field:
nbc = self.force_field["PairIJ Coeffs"]
nbc = nbc.sort_values(["id1", "id2"]).drop(["id1", "id2"], axis=1)
nonbond_coeffs = [list(t) for t in nbc.itertuples(False, None)]
elif "Pair Coeffs" in self.force_field:
nbc = self.force_field["Pair Coeffs"].sort_index()
nonbond_coeffs = [list(t) for t in nbc.itertuples(False, None)]
topo_coeffs = {k: [] for k in SECTION_KEYWORDS["ff"][2:]
if k in self.force_field}
for kw in topo_coeffs.keys():
class2_coeffs = {k: list(v.itertuples(False, None))
for k, v in self.force_field.items()
if k in CLASS2_KEYWORDS.get(kw, [])}
ff_df = self.force_field[kw]
for t in ff_df.itertuples(True, None):
d = {"coeffs": list(t[1:]), "types": []}
if class2_coeffs:
d.update({k: list(v[t[0] - 1])
for k, v in class2_coeffs.items()})
topo_coeffs[kw].append(d)
if self.topology:
label_topo = lambda t: tuple(masses.loc[atoms_df.loc[t, "type"],
"label"])
for k, v in self.topology.items():
ff_kw = k[:-1] + " Coeffs"
for topo in v.itertuples(False, None):
topo_idx = topo[0] - 1
indices = topo[1:]
mids = atoms_df.loc[indices, "molecule-ID"].unique()
assert len(mids) == 1, \
"Do not support intermolecular topology formed " \
"by atoms with different molecule-IDs"
label = label_topo(indices)
topo_coeffs[ff_kw][topo_idx]["types"].append(label)
if data_by_mols[mids[0]].get(k):
data_by_mols[mids[0]][k].append(indices)
else:
data_by_mols[mids[0]][k] = [indices]
if topo_coeffs:
for v in topo_coeffs.values():
for d in v:
d["types"] = list(set(d["types"]))
ff = ForceField(mass_info=mass_info, nonbond_coeffs=nonbond_coeffs,
topo_coeffs=topo_coeffs)
topo_list = []
for mid in unique_mids:
data = data_by_mols[mid]
atoms = data["Atoms"]
shift = min(atoms.index)
type_ids = atoms["type"]
species = masses.loc[type_ids, "element"]
labels = masses.loc[type_ids, "label"]
coords = atoms[["x", "y", "z"]]
m = Molecule(species.values, coords.values,
site_properties={ff_label: labels.values})
charges = atoms.get("q")
velocities = atoms[["vx", "vy", "vz"]] if "vx" in atoms.columns \
else None
topologies = {}
for kw in SECTION_KEYWORDS["topology"]:
if data.get(kw):
topologies[kw] = (np.array(data[kw]) - shift).tolist()
topologies = None if not topologies else topologies
topo_list.append(Topology(sites=m, ff_label=ff_label,
charges=charges, velocities=velocities,
topologies=topologies))
return self.box, ff, topo_list
[docs] @classmethod
def from_file(cls, filename, atom_style="full", sort_id=False):
"""
Constructor that parses a file.
Args:
filename (str): Filename to read.
atom_style (str): Associated atom_style. Default to "full".
sort_id (bool): Whether sort each section by id. Default to
True.
"""
with open(filename) as f:
lines = f.readlines()
kw_pattern = r"|".join(itertools.chain(*SECTION_KEYWORDS.values()))
section_marks = [i for i, l in enumerate(lines)
if re.search(kw_pattern, l)]
parts = np.split(lines, section_marks)
float_group = r"([0-9eE.+-]+)"
header_pattern = dict()
header_pattern["counts"] = r"^\s*(\d+)\s+([a-zA-Z]+)$"
header_pattern["types"] = r"^\s*(\d+)\s+([a-zA-Z]+)\s+types$"
header_pattern["bounds"] = r"^\s*{}$".format(r"\s+".join(
[float_group] * 2 + [r"([xyz])lo \3hi"]))
header_pattern["tilt"] = r"^\s*{}$".format(r"\s+".join(
[float_group] * 3 + ["xy xz yz"]))
header = {"counts": {}, "types": {}}
bounds = {}
for l in clean_lines(parts[0][1:]): # skip the 1st line
match = None
for k, v in header_pattern.items():
match = re.match(v, l)
if match:
break
else:
continue
if match and k in ["counts", "types"]:
header[k][match.group(2)] = int(match.group(1))
elif match and k == "bounds":
g = match.groups()
bounds[g[2]] = [float(i) for i in g[:2]]
elif match and k == "tilt":
header["tilt"] = [float(i) for i in match.groups()]
header["bounds"] = [bounds.get(i, [-0.5, 0.5]) for i in "xyz"]
box = LammpsBox(header["bounds"], header.get("tilt"))
def parse_section(sec_lines):
title_info = sec_lines[0].split("#", 1)
kw = title_info[0].strip()
sio = StringIO("".join(sec_lines[2:])) # skip the 2nd line
df = pd.read_csv(sio, header=None, comment="#",
delim_whitespace=True)
if kw.endswith("Coeffs") and not kw.startswith("PairIJ"):
names = ["id"] + ["coeff%d" % i
for i in range(1, df.shape[1])]
elif kw == "PairIJ Coeffs":
names = ["id1", "id2"] + ["coeff%d" % i
for i in range(1, df.shape[1] - 1)]
df.index.name = None
elif kw in SECTION_HEADERS:
names = ["id"] + SECTION_HEADERS[kw]
elif kw == "Atoms":
names = ["id"] + ATOMS_HEADERS[atom_style]
if df.shape[1] == len(names):
pass
elif df.shape[1] == len(names) + 3:
names += ["nx", "ny", "nz"]
else:
raise ValueError("Format in Atoms section inconsistent"
" with atom_style %s" % atom_style)
else:
raise NotImplementedError("Parser for %s section"
" not implemented" % kw)
df.columns = names
if sort_id:
sort_by = "id" if kw != "PairIJ Coeffs" else ["id1", "id2"]
df.sort_values(sort_by, inplace=True)
if "id" in df.columns:
df.set_index("id", drop=True, inplace=True)
df.index.name = None
return kw, df
err_msg = "Bad LAMMPS data format where "
body = {}
seen_atoms = False
for part in parts[1:]:
name, section = parse_section(part)
if name == "Atoms":
seen_atoms = True
if name in ["Velocities"] + SECTION_KEYWORDS["topology"] and \
not seen_atoms: # Atoms must appear earlier than these
raise RuntimeError(err_msg + "%s section appears before"
" Atoms section" % name)
body.update({name: section})
err_msg += "Nos. of {} do not match between header and {} section"
assert len(body["Masses"]) == header["types"]["atom"], \
err_msg.format("atom types", "Masses")
atom_sections = ["Atoms", "Velocities"] \
if "Velocities" in body else ["Atoms"]
for s in atom_sections:
assert len(body[s]) == header["counts"]["atoms"], \
err_msg.format("atoms", s)
for s in SECTION_KEYWORDS["topology"]:
if header["counts"].get(s.lower(), 0) > 0:
assert len(body[s]) == header["counts"][s.lower()], \
err_msg.format(s.lower(), s)
items = {k.lower(): body[k] for k in ["Masses", "Atoms"]}
items["velocities"] = body.get("Velocities")
ff_kws = [k for k in body if k
in SECTION_KEYWORDS["ff"] + SECTION_KEYWORDS["class2"]]
items["force_field"] = {k: body[k] for k in ff_kws} if ff_kws \
else None
topo_kws = [k for k in body if k in SECTION_KEYWORDS["topology"]]
items["topology"] = {k: body[k] for k in topo_kws} \
if topo_kws else None
items["atom_style"] = atom_style
items["box"] = box
return cls(**items)
[docs] @classmethod
def from_ff_and_topologies(cls, box, ff, topologies, atom_style="full"):
"""
Constructor building LammpsData from a ForceField object and a
list of Topology objects. Do not support intermolecular
topologies since a Topology object includes data for ONE
molecule or structure only.
Args:
box (LammpsBox): Simulation box.
ff (ForceField): ForceField object with data for Masses and
force field sections.
topologies ([Topology]): List of Topology objects with data
for Atoms, Velocities and topology sections.
atom_style (str): Output atom_style. Default to "full".
"""
atom_types = set.union(*[t.species for t in topologies])
assert atom_types.issubset(ff.maps["Atoms"].keys()),\
"Unknown atom type found in topologies"
items = dict(box=box, atom_style=atom_style, masses=ff.masses,
force_field=ff.force_field)
mol_ids, charges, coords, labels = [], [], [], []
v_collector = [] if topologies[0].velocities else None
topo_collector = {"Bonds": [], "Angles": [], "Dihedrals": [],
"Impropers": []}
topo_labels = {"Bonds": [], "Angles": [], "Dihedrals": [],
"Impropers": []}
for i, topo in enumerate(topologies):
if topo.topologies:
shift = len(labels)
for k, v in topo.topologies.items():
topo_collector[k].append(np.array(v) + shift + 1)
topo_labels[k].extend([tuple([topo.type_by_sites[j]
for j in t]) for t in v])
if isinstance(v_collector, list):
v_collector.append(topo.velocities)
mol_ids.extend([i + 1] * len(topo.sites))
labels.extend(topo.type_by_sites)
coords.append(topo.sites.cart_coords)
q = [0.0] * len(topo.sites) if not topo.charges else topo.charges
charges.extend(q)
atoms = pd.DataFrame(np.concatenate(coords), columns=["x", "y", "z"])
atoms["molecule-ID"] = mol_ids
atoms["q"] = charges
atoms["type"] = list(map(ff.maps["Atoms"].get, labels))
atoms.index += 1
atoms = atoms[ATOMS_HEADERS[atom_style]]
velocities = None
if v_collector:
velocities = pd.DataFrame(np.concatenate(v_collector),
columns=SECTION_HEADERS["Velocities"])
velocities.index += 1
topology = {k: None for k, v in topo_labels.items() if len(v) > 0}
for k in topology:
df = pd.DataFrame(np.concatenate(topo_collector[k]),
columns=SECTION_HEADERS[k][1:])
df["type"] = list(map(ff.maps[k].get, topo_labels[k]))
if any(pd.isnull(df["type"])): # Throw away undefined topologies
warnings.warn("Undefined %s detected and removed" % k.lower())
df.dropna(subset=["type"], inplace=True)
df.reset_index(drop=True, inplace=True)
df.index += 1
topology[k] = df[SECTION_HEADERS[k]]
topology = {k: v for k, v in topology.items() if not v.empty}
items.update({"atoms": atoms, "velocities": velocities,
"topology": topology})
return cls(**items)
[docs] @classmethod
def from_structure(cls, structure, ff_elements=None, atom_style="charge"):
"""
Simple constructor building LammpsData from a structure without
force field parameters and topologies.
Args:
structure (Structure): Input structure.
ff_elements ([str]): List of strings of elements that must
be present due to force field settings but not
necessarily in the structure. Default to None.
atom_style (str): Choose between "atomic" (neutral) and
"charge" (charged). Default to "charge".
"""
s = structure.get_sorted_structure()
box, symmop = lattice_2_lmpbox(s.lattice)
coords = symmop.operate_multi(s.cart_coords)
site_properties = s.site_properties
if "velocities" in site_properties:
velos = np.array(s.site_properties["velocities"])
rot = SymmOp.from_rotation_and_translation(symmop.rotation_matrix)
rot_velos = rot.operate_multi(velos)
site_properties.update({"velocities": rot_velos})
boxed_s = Structure(box.to_lattice(), s.species, coords,
site_properties=site_properties,
coords_are_cartesian=True)
symbols = list(s.symbol_set)
if ff_elements:
symbols.extend(ff_elements)
elements = sorted(Element(el) for el in set(symbols))
mass_info = [tuple([i.symbol] * 2) for i in elements]
ff = ForceField(mass_info)
topo = Topology(boxed_s)
return cls.from_ff_and_topologies(box=box, ff=ff, topologies=[topo],
atom_style=atom_style)
[docs] @classmethod
def from_dict(cls, d):
decode_df = lambda s: pd.read_json(s, orient="split")
items = dict()
items["box"] = LammpsBox.from_dict(d["box"])
items["masses"] = decode_df(d["masses"])
items["atoms"] = decode_df(d["atoms"])
items["atom_style"] = d["atom_style"]
velocities = d["velocities"]
if velocities:
velocities = decode_df(velocities)
items["velocities"] = velocities
force_field = d["force_field"]
if force_field:
force_field = {k: decode_df(v) for k, v in force_field.items()}
items["force_field"] = force_field
topology = d["topology"]
if topology:
topology = {k: decode_df(v) for k, v in topology.items()}
items["topology"] = topology
return cls(**items)
[docs] def as_dict(self):
encode_df = lambda df: df.to_json(orient="split")
d = dict()
d["@module"] = self.__class__.__module__
d["@class"] = self.__class__.__name__
d["box"] = self.box.as_dict()
d["masses"] = encode_df(self.masses)
d["atoms"] = encode_df(self.atoms)
d["atom_style"] = self.atom_style
d["velocities"] = None if self.velocities is None \
else encode_df(self.velocities)
d["force_field"] = None if not self.force_field \
else {k: encode_df(v) for k, v in self.force_field.items()}
d["topology"] = None if not self.topology \
else {k: encode_df(v) for k, v in self.topology.items()}
return d
[docs]class Topology(MSONable):
"""
Class carrying most data in Atoms, Velocities and molecular
topology sections for ONE SINGLE Molecule or Structure
object, or a plain list of Sites.
"""
def __init__(self, sites, ff_label=None, charges=None, velocities=None,
topologies=None):
"""
Args:
sites ([Site] or SiteCollection): A group of sites in a
list or as a Molecule/Structure.
ff_label (str): Site property key for labeling atoms of
different types. Default to None, i.e., use
site.species_string.
charges ([q, ...]): Charge of each site in a (n,)
array/list, where n is the No. of sites. Default to
None, i.e., search site property for charges.
velocities ([[vx, vy, vz], ...]): Velocity of each site in
a (n, 3) array/list, where n is the No. of sites.
Default to None, i.e., search site property for
velocities.
topologies (dict): Bonds, angles, dihedrals and improper
dihedrals defined by site indices. Default to None,
i.e., no additional topology. All four valid keys
listed below are optional.
{
"Bonds": [[i, j], ...],
"Angles": [[i, j, k], ...],
"Dihedrals": [[i, j, k, l], ...],
"Impropers": [[i, j, k, l], ...]
}
"""
if not isinstance(sites, (Molecule, Structure)):
sites = Molecule.from_sites(sites)
if ff_label:
type_by_sites = sites.site_properties.get(ff_label)
else:
type_by_sites = [site.specie.symbol for site in sites]
# search for site property if not override
if charges is None:
charges = sites.site_properties.get("charge")
if velocities is None:
velocities = sites.site_properties.get("velocities")
# validate shape
if charges is not None:
charge_arr = np.array(charges)
assert charge_arr.shape == (len(sites),),\
"Wrong format for charges"
charges = charge_arr.tolist()
if velocities is not None:
velocities_arr = np.array(velocities)
assert velocities_arr.shape == (len(sites), 3), \
"Wrong format for velocities"
velocities = velocities_arr.tolist()
if topologies:
topologies = {k: v for k, v in topologies.items()
if k in SECTION_KEYWORDS["topology"]}
self.sites = sites
self.ff_label = ff_label
self.charges = charges
self.velocities = velocities
self.topologies = topologies
self.type_by_sites = type_by_sites
self.species = set(type_by_sites)
[docs] @classmethod
def from_bonding(cls, molecule, bond=True, angle=True, dihedral=True,
tol=0.1, **kwargs):
"""
Another constructor that creates an instance from a molecule.
Covalent bonds and other bond-based topologies (angles and
dihedrals) can be automatically determined. Cannot be used for
non bond-based topologies, e.g., improper dihedrals.
Args:
molecule (Molecule): Input molecule.
bond (bool): Whether find bonds. If set to False, angle and
dihedral searching will be skipped. Default to True.
angle (bool): Whether find angles. Default to True.
dihedral (bool): Whether find dihedrals. Default to True.
tol (float): Bond distance tolerance. Default to 0.1.
Not recommended to alter.
**kwargs: Other kwargs supported by Topology.
"""
real_bonds = molecule.get_covalent_bonds(tol=tol)
bond_list = [list(map(molecule.index, [b.site1, b.site2]))
for b in real_bonds]
if not all((bond, bond_list)):
# do not search for others if not searching for bonds or no bonds
return cls(sites=molecule, **kwargs)
else:
angle_list, dihedral_list = [], []
dests, freq = np.unique(bond_list, return_counts=True)
hubs = dests[np.where(freq > 1)]
bond_arr = np.array(bond_list)
if len(hubs) > 0:
hub_spokes = {}
for hub in hubs:
ix = np.any(np.isin(bond_arr, hub), axis=1)
bonds = list(np.unique(bond_arr[ix]))
bonds.remove(hub)
hub_spokes[hub] = bonds
# skip angle or dihedral searching if too few bonds or hubs
dihedral = False if len(bond_list) < 3 or len(hubs) < 2 \
else dihedral
angle = False if len(bond_list) < 2 or len(hubs) < 1 else angle
if angle:
for k, v in hub_spokes.items():
angle_list.extend([[i, k, j] for i, j in
itertools.combinations(v, 2)])
if dihedral:
hub_cons = bond_arr[np.all(np.isin(bond_arr, hubs), axis=1)]
for i, j in hub_cons:
ks = [k for k in hub_spokes[i] if k != j]
ls = [l for l in hub_spokes[j] if l != i]
dihedral_list.extend([[k, i, j, l] for k,l in
itertools.product(ks, ls)
if k != l])
topologies = {k: v for k, v
in zip(SECTION_KEYWORDS["topology"][:3],
[bond_list, angle_list, dihedral_list])
if len(v) > 0}
topologies = None if len(topologies) == 0 else topologies
return cls(sites=molecule, topologies=topologies, **kwargs)
[docs]class ForceField(MSONable):
"""
Class carrying most data in Masses and force field sections.
Attributes:
masses (pandas.DataFrame): DataFrame for Masses section.
force_field (dict): Force field section keywords (keys) and
data (values) as DataFrames.
maps (dict): Dict for labeling atoms and topologies.
"""
_is_valid = lambda self, df: not pd.isnull(df).values.any()
def __init__(self, mass_info, nonbond_coeffs=None, topo_coeffs=None):
"""
Args:
mass_into (list): List of atomic mass info. Elements,
strings (symbols) and floats are all acceptable for the
values, with the first two converted to the atomic mass
of an element. It is recommended to use
OrderedDict.items() to prevent key duplications.
[("C", 12.01), ("H", Element("H")), ("O", "O"), ...]
nonbond_coeffs [coeffs]: List of pair or pairij
coefficients, of which the sequence must be sorted
according to the species in mass_dict. Pair or PairIJ
determined by the length of list. Optional with default
to None.
topo_coeffs (dict): Dict with force field coefficients for
molecular topologies. Optional with default
to None. All four valid keys listed below are optional.
Each value is a list of dicts with non optional keys
"coeffs" and "types", and related class2 force field
keywords as optional keys.
{
"Bond Coeffs":
[{"coeffs": [coeff],
"types": [("C", "C"), ...]}, ...],
"Angle Coeffs":
[{"coeffs": [coeff],
"BondBond Coeffs": [coeff],
"types": [("H", "C", "H"), ...]}, ...],
"Dihedral Coeffs":
[{"coeffs": [coeff],
"BondBond13 Coeffs": [coeff],
"types": [("H", "C", "C", "H"), ...]}, ...],
"Improper Coeffs":
[{"coeffs": [coeff],
"AngleAngle Coeffs": [coeff],
"types": [("H", "C", "C", "H"), ...]}, ...],
}
Topology of same type or equivalent types (e.g.,
("C", "H") and ("H", "C") bonds) are NOT ALLOWED to
be defined MORE THAN ONCE with DIFFERENT coefficients.
"""
map_mass = lambda v: v.atomic_mass.real if isinstance(v, Element) \
else Element(v).atomic_mass.real if isinstance(v, string_types) \
else v
index, masses, self.mass_info, atoms_map = [], [], [], {}
for i, m in enumerate(mass_info):
index.append(i + 1)
mass = map_mass(m[1])
masses.append(mass)
self.mass_info.append((m[0], mass))
atoms_map[m[0]] = i + 1
self.masses = pd.DataFrame({"mass": masses}, index=index)
self.maps = {"Atoms": atoms_map}
ff_dfs = {}
self.nonbond_coeffs = nonbond_coeffs
if self.nonbond_coeffs:
ff_dfs.update(self._process_nonbond())
self.topo_coeffs = topo_coeffs
if self.topo_coeffs:
self.topo_coeffs = {k: v for k, v in self.topo_coeffs.items()
if k in SECTION_KEYWORDS["ff"][2:]}
for k in self.topo_coeffs.keys():
coeffs, mapper = self._process_topo(k)
ff_dfs.update(coeffs)
self.maps.update(mapper)
self.force_field = None if len(ff_dfs) == 0 else ff_dfs
def _process_nonbond(self):
pair_df = pd.DataFrame(self.nonbond_coeffs)
assert self._is_valid(pair_df), \
"Invalid nonbond coefficients with rows varying in length"
npair, ncoeff = pair_df.shape
pair_df.columns = ["coeff%d" % i for i in range(1, ncoeff + 1)]
nm = len(self.mass_info)
ncomb = int(nm * (nm + 1) / 2)
if npair == nm:
kw = "Pair Coeffs"
pair_df.index = range(1, nm + 1)
elif npair == ncomb:
kw = "PairIJ Coeffs"
ids = list(itertools.
combinations_with_replacement(range(1, nm + 1), 2))
id_df = pd.DataFrame(ids, columns=["id1", "id2"])
pair_df = pd.concat([id_df, pair_df], axis=1)
else:
raise ValueError("Expecting {} Pair Coeffs or "
"{} PairIJ Coeffs for {} atom types,"
" got {}".format(nm, ncomb, nm, npair))
return {kw: pair_df}
def _process_topo(self, kw):
def find_eq_types(label, section):
if section.startswith("Improper"):
label_arr = np.array(label)
seqs = [[0, 1, 2, 3], [0, 2, 1, 3],
[3, 1, 2, 0], [3, 2, 1, 0]]
return [tuple(label_arr[s]) for s in seqs]
else:
return [label] + [label[::-1]]
main_data, distinct_types = [], []
class2_data = {k: [] for k in self.topo_coeffs[kw][0].keys()
if k in CLASS2_KEYWORDS.get(kw, [])}
for i, d in enumerate(self.topo_coeffs[kw]):
main_data.append(d["coeffs"])
distinct_types.append(d["types"])
for k in class2_data.keys():
class2_data[k].append(d[k])
distinct_types = [set(itertools.
chain(*[find_eq_types(t, kw)
for t in dt])) for dt in distinct_types]
type_counts = sum([len(dt) for dt in distinct_types])
type_union = set.union(*distinct_types)
assert len(type_union) == type_counts, "Duplicated items found " \
"under different coefficients in %s" % kw
atoms = set(np.ravel(list(itertools.chain(*distinct_types))))
assert atoms.issubset(self.maps["Atoms"].keys()), \
"Undefined atom type found in %s" % kw
mapper = {}
for i, dt in enumerate(distinct_types):
for t in dt:
mapper[t] = i + 1
def process_data(data):
df = pd.DataFrame(data)
assert self._is_valid(df),\
"Invalid coefficients with rows varying in length"
n, c = df.shape
df.columns = ["coeff%d" % i for i in range(1, c + 1)]
df.index = range(1, n + 1)
return df
all_data = {kw: process_data(main_data)}
if class2_data:
all_data.update({k: process_data(v) for k, v
in class2_data.items()})
return all_data, {kw[:-7] + "s": mapper}
[docs] def to_file(self, filename):
"""
Saves object to a file in YAML format.
Args:
filename (str): Filename.
"""
d = {"mass_info": self.mass_info,
"nonbond_coeffs": self.nonbond_coeffs,
"topo_coeffs": self.topo_coeffs}
yaml = YAML(typ="safe")
with open(filename, "w") as f:
yaml.dump(d, f)
[docs] @classmethod
def from_file(cls, filename):
"""
Constructor that reads in a file in YAML format.
Args:
filename (str): Filename.
"""
yaml = YAML(typ="safe")
with open(filename, "r") as f:
d = yaml.load(f)
return cls.from_dict(d)
[docs] @classmethod
def from_dict(cls, d):
d["mass_info"] = [tuple(m) for m in d["mass_info"]]
if d.get("topo_coeffs"):
for v in d["topo_coeffs"].values():
for c in v:
c["types"] = [tuple(t) for t in c["types"]]
return cls(d["mass_info"], d["nonbond_coeffs"], d["topo_coeffs"])
@deprecated(LammpsData.from_structure,
"structure_2_lmpdata has been deprecated "
"in favor of LammpsData.from_structure")
def structure_2_lmpdata(structure, ff_elements=None, atom_style="charge"):
"""
Converts a structure to a LammpsData object with no force field
parameters and topologies.
Args:
structure (Structure): Input structure.
ff_elements ([str]): List of strings of elements that must be
present due to force field settings but not necessarily in
the structure. Default to None.
atom_style (str): Choose between "atomic" (neutral) and
"charge" (charged). Default to "charge".
Returns:
LammpsData
"""
s = structure.get_sorted_structure()
a, b, c = s.lattice.abc
m = s.lattice.matrix
xhi = a
xy = np.dot(m[1], m[0] / xhi)
yhi = np.sqrt(b ** 2 - xy ** 2)
xz = np.dot(m[2], m[0] / xhi)
yz = (np.dot(m[1], m[2]) - xy * xz) / yhi
zhi = np.sqrt(c ** 2 - xz ** 2 - yz ** 2)
box_bounds = [[0.0, xhi], [0.0, yhi], [0.0, zhi]]
box_tilt = [xy, xz, yz]
box_tilt = None if not any(box_tilt) else box_tilt
box = LammpsBox(box_bounds, box_tilt)
new_latt = Lattice([[xhi, 0, 0], [xy, yhi, 0], [xz, yz, zhi]])
s.modify_lattice(new_latt)
symbols = list(s.symbol_set)
if ff_elements:
symbols.extend(ff_elements)
elements = sorted(Element(el) for el in set(symbols))
mass_info = [tuple([i.symbol] * 2) for i in elements]
ff = ForceField(mass_info)
topo = Topology(s)
return LammpsData.from_ff_and_topologies(box=box, ff=ff, topologies=[topo],
atom_style=atom_style)