calc = Calculator(nbands=8, h=0.2, txt='O2.txt', tolerance=1e-9)
O2.set_calculator(calc)
e0 = O2.get_potential_energy()
f = O2.get_forces()
#equal(2.1062, sum(abs(f.ravel())), 1e-2)
calc.write('O2.gpw')
print e0, f
O2.positions[1] = (1.21 + d, d, d)
e2 = O2.get_potential_energy()
niter2 = calc.niter
f2 = O2.get_forces()
del calc, O2
if 1:
atoms = Calculator('O2.gpw', txt='O2-restart.txt',
tolerance=1e-9).get_atoms()
e = atoms.get_potential_energy()
atoms.positions[1] = (1.21 + d, d, d)
e1 = atoms.get_potential_energy()
f1 = atoms.get_forces()
niter1 = atoms.get_calculator().niter
print e1, e2
print niter1, niter2
print sum(abs(f1.ravel() - f2.ravel()))
print f1, f2, f1 - f2
equal(e1, e2, 3e-5)
equal(niter1, niter2, 0)
equal(sum(abs(f1.ravel() - f2.ravel())), 0.0, 0.002)
e0 = O2.get_potential_energy()
f = O2.get_forces()
#equal(2.1062, sum(abs(f.ravel())), 1e-2)
calc.write('O2.gpw')
print e0, f
O2.positions[1] = (1.21+d,d,d)
e2 = O2.get_potential_energy()
niter2 = calc.niter
f2 = O2.get_forces()
del calc,O2
if 1:
atoms = Calculator('O2.gpw', txt='O2-restart.txt',
tolerance=1e-9).get_atoms()
e = atoms.get_potential_energy()
atoms.positions[1] = (1.21+d,d,d)
e1 = atoms.get_potential_energy()
f1 = atoms.get_forces()
niter1 = atoms.get_calculator().niter
print e1,e2
print niter1,niter2
print sum(abs(f1.ravel()-f2.ravel()))
print f1,f2, f1-f2
equal(e1,e2,3e-5)
equal(niter1,niter2,0)
equal(sum(abs(f1.ravel()-f2.ravel())),0.0,0.002)
