Chimie Théorique » QMX

from ase.atoms import Atoms

from ase.units import Bohr

def read_dftb(filename='dftb_in.hsd'):

    """Method to read coordinates form DFTB+ input file dftb_in.hsd

    additionally read information about fixed atoms

    and periodic boundary condition

    """

    from ase import Atoms, Atom

    from ase.constraints import FixAtoms

    import sys, string

    if isinstance(filename, str):

        f = open(filename)

    lines = f.readlines()

    atoms_pos = []

    atom_symbols = []

    type_names = []

    my_pbc = False

    myconstraints=[]

    moved_atoms_found = False

    range_found = False

    moved_atoms = []

    for line in lines:

        if (line.strip().startswith('#')):

            pass

        else:

            if ('TypeNames' in line):

                col=line.split()

                for i in range(3,len(col)-1):

                    type_names.append(col[i].strip("\""))

            elif ('Periodic' in line):

                if ('Yes' in line):

                    my_pbc = True

            else:

                pass

    start_reading_coords=False

    stop_reading_coords=False

    for line in lines:

        if (line.strip().startswith('#')):

            pass

        else:

            if ('TypesAndCoordinates' in line):

                start_reading_coords=True

            if start_reading_coords:

                if ('}' in line):

                    stop_reading_coords=True

            if (start_reading_coords and not(stop_reading_coords)

            and not 'TypesAndCoordinates' in line):

                typeindexstr, x, y, z = line.split()[:4]

                typeindex=int(typeindexstr)

                symbol=type_names[typeindex-1]

                atom_symbols.append(symbol)

                atoms_pos.append([float(x), float(y), float(z)])

    if type(filename) == str:

        f.close()

    atoms = Atoms(positions = atoms_pos, symbols = atom_symbols, pbc = my_pbc)

    return atoms

def write_dftb(filename,atoms):

    """Method to write coordinates in DFTB+ format

    """

    import numpy as np

    from ase.constraints import FixAtoms

    if isinstance(filename, str):

        f = open(filename)

    lines = f.readlines()

    if type(filename) == str:

        f.close()

    if isinstance(filename, str):

        f = open(filename, 'w')

    else: # Assume it's a 'file-like object'

        f = filename

    coord = atoms.get_positions()

    symbols = atoms.get_chemical_symbols()

    start_writing_coords = False

    stop_writing_coords = False

    i=0

    for line in lines:

        if ('TypesAndCoordinates' in line):

            start_writing_coords=True

        if (start_writing_coords and not(stop_writing_coords)):

            if ('}' in line):

                stop_writing_coords = True

        if (start_writing_coords and not(stop_writing_coords)and 

            not ('TypesAndCoordinates' in line)):

            atom_type_index = line.split()[0]

            f.write('%6s  %20.14f  %20.14f  %20.14f\n'

                    % (atom_type_index,coord[i][0],coord[i][1],coord[i][2]))

            i=i+1

        else:

            f.write(line)