[gpaw-users] trajectory file

[Daniel Torres]

Hi guys!
Im using the following Py file. I notice that the trajectory file 
generated is empty. Is this normal?
Best regards
Dani

#!/usr/bin/env python
from ase import *
from gpaw import*


a=2*5.8776599999999997
b=2*5.6615700000000002
L=26.0000000000000000

bulk = Atoms([  Atom('Ni',(-1.0527,2.0821,17.0359),magmom=1.0),
Atom('Ni',(1.3186,2.3110,16.9651),magmom=1.0),
Atom('Ni',(-0.0903,4.1794,16.8498),magmom=1.0),
Atom('Ni',(-0.0028,2.8824,18.8402),magmom=1.0),
Atom('C',(-0.0376,2.8430,20.4907),magmom=0.0),
Atom('O',(-0.0376,2.8430,22.0000),magmom=0.0)],
            cell=(a,b,L),
            pbc=(True, True, False),
            constraint=FixAtoms(range( 0))   )
bulk.center(axis=2)
calc = GPAW(nbands= 50 ,
               xc='RPBE',
               spinpol=True,
#              eigensolver='dav',
#              mixer=MixerSum(0.1, 5, 'new', 100.0),
               mixer=MixerSum(0.1, 5,  weight=100.0),
               maxiter=120,
               kpts=(1,1,1),
               h=0.20,
               width=0.1,
#              usesymm=True,
               txt='slab.txt')
bulk.set_calculator(calc)
traj = PickleTrajectory('cell.traj', 'w', bulk)
relax = QuasiNewton(bulk)
relax.run(fmax=0.01)
energy = bulk.get_potential_energy()