Source code for pymatgen.io.xyz

# coding: utf-8
# Copyright (c) Pymatgen Development Team.
# Distributed under the terms of the MIT License.

from __future__ import division, unicode_literals
import re

from pymatgen.core.structure import Molecule
from monty.io import zopen

"""
Module implementing an XYZ file object class.
"""

__author__ = "Shyue Ping Ong"
__copyright__ = "Copyright 2012, The Materials Project"
__version__ = "0.1"
__maintainer__ = "Shyue Ping Ong"
__email__ = "shyuep@gmail.com"
__date__ = "Apr 17, 2012"


[docs]class XYZ(object): """ Basic class for importing and exporting Molecules or Structures in XYZ format. Args: mol: Input molecule or list of molecules .. note:: Exporting periodic structures in the XYZ format will lose information about the periodicity. Essentially, only cartesian coordinates are written in this format and no information is retained about the lattice. """ def __init__(self, mol, coord_precision=6): if isinstance(mol, Molecule) or not isinstance(mol, list): self._mols = [mol] else: self._mols = mol self.precision = coord_precision @property def molecule(self): """ Returns molecule associated with this XYZ. In case multiple frame XYZ, returns the last frame. """ return self._mols[-1] @property def all_molecules(self): """ Returns all the frames of molecule associated with this XYZ. """ return self._mols @staticmethod def _from_frame_string(contents): """ Convert a single frame XYZ string to a molecule """ lines = contents.split("\n") num_sites = int(lines[0]) coords = [] sp = [] coord_patt = re.compile( r"(\w+)\s+([0-9\-\.e]+)\s+([0-9\-\.e]+)\s+([0-9\-\.e]+)" ) for i in range(2, 2 + num_sites): m = coord_patt.search(lines[i]) if m: sp.append(m.group(1)) # this is 1-indexed # this is 0-indexed coords.append([float(j) for j in m.groups()[1:4]]) return Molecule(sp, coords)
[docs] @staticmethod def from_string(contents): """ Creates XYZ object from a string. Args: contents: String representing an XYZ file. Returns: XYZ object """ if contents[-1] != "\n": contents += "\n" white_space = r"[ \t\r\f\v]" natoms_line = white_space + r"*\d+" + white_space + r"*\n" comment_line = r"[^\n]*\n" coord_lines = r"(\s*\w+\s+[0-9\-\.e]+\s+[0-9\-\.e]+\s+[0-9\-\.e]+\s*\n)+" frame_pattern_text = natoms_line + comment_line + coord_lines pat = re.compile(frame_pattern_text, re.MULTILINE) mols = [] for xyz_match in pat.finditer(contents): xyz_text = xyz_match.group(0) mols.append(XYZ._from_frame_string(xyz_text)) return XYZ(mols)
[docs] @staticmethod def from_file(filename): """ Creates XYZ object from a file. Args: filename: XYZ filename Returns: XYZ object """ with zopen(filename) as f: return XYZ.from_string(f.read())
def _frame_str(self, frame_mol): output = [str(len(frame_mol)), frame_mol.composition.formula] fmtstr = "{{}} {{:.{0}f}} {{:.{0}f}} {{:.{0}f}}".format(self.precision) for site in frame_mol: output.append(fmtstr.format(site.specie, site.x, site.y, site.z)) return "\n".join(output) def __str__(self): return "\n".join([self._frame_str(mol) for mol in self._mols])
[docs] def write_file(self, filename): """ Writes XYZ to file. Args: filename: File name of output file. """ with zopen(filename, "wt") as f: f.write(self.__str__())