Chimie Théorique » QMX

import os

from ase import Atom, Atoms

from ase.io import PickleTrajectory

co = Atoms([Atom('C', (0, 0, 0)),

            Atom('O', (0, 0, 1.2))])

traj = PickleTrajectory('1.traj', 'w', co)

for i in range(5):

    co.positions[:, 2] += 0.1

    traj.write()

del traj

traj = PickleTrajectory('1.traj', 'a')

co = traj[-1]

print co.positions

co.positions[:] += 1

traj.write(co)

del traj

t = PickleTrajectory('1.traj', 'a')

print t[-1].positions

print '.--------'

for a in t:

    print 1, a.positions[-1,2]

co.positions[:] += 1

t.write(co)

for a in t:

    print 2, a.positions[-1,2]

assert len(t) == 7

# append to a nonexisting file

fname = '2.traj'

if os.path.isfile(fname):

    os.remove(fname)

t = PickleTrajectory(fname, 'a', co)

del(t)

os.remove(fname)