from ase_ext import Atom, Atoms
from ase_ext.calculators.lj import LennardJones
from ase_ext.constraints import FixBondLength
dimer = Atoms([Atom('X',
(0, 0, 0)), Atom('X', (0, 0, 1))],
calculator=LennardJones(),
constraint=FixBondLength(0, 1))
print(dimer.get_forces())
print(dimer.positions)
dimer.positions[:] += 0.1
print(dimer.positions)
dimer.positions[:, 2] += 5.1
print(dimer.positions)
dimer.positions[:] = [(1, 2, 3), (4, 5, 6)]
print(dimer.positions)
dimer.set_positions([(1, 2, 3), (4, 5, 6.2)])
print(dimer.positions)
from ase_ext.optimize.lbfgs import LBFGS
from ase_ext.optimize.mdmin import MDMin
try:
from asap3 import EMT
except ImportError:
pass
else:
a = 3.6
b = a / 2
cu = Atoms('Cu', cell=[(0, b, b), (b, 0, b), (b, b, 0)], pbc=1) * (6, 6, 6)
cu.set_calculator(EMT())
f = UnitCellFilter(cu, [1, 1, 1, 0, 0, 0])
opt = LBFGS(f)
t = PickleTrajectory('Cu-fcc.traj', 'w', cu)
opt.attach(t)
opt.run(5.0)
# HCP:
from ase_ext.lattice.surface import hcp0001
cu = hcp0001('Cu', (1, 1, 2), a=a / sqrt(2))
cu.cell[1, 0] += 0.05
cu *= (6, 6, 3)
cu.set_calculator(EMT())
print(cu.get_forces())
print(cu.get_stress())
f = UnitCellFilter(cu)
opt = MDMin(f, dt=0.01)
t = PickleTrajectory('Cu-hcp.traj', 'w', cu)
opt.attach(t)
opt.run(0.2)
import numpy as np
from ase_ext import Atoms
from ase_ext.units import fs
from ase_ext.calculators.test import TestPotential
from ase_ext.calculators.emt import EMT
from ase_ext.md import VelocityVerlet
from ase_ext.io import PickleTrajectory, read
from ase_ext.optimize import QuasiNewton
np.seterr(all='raise')
a = Atoms('4X',
masses=[1, 2, 3, 4],
positions=[(0, 0, 0), (1, 0, 0), (0, 1, 0), (0.1, 0.2, 0.7)],
calculator=TestPotential())
print(a.get_forces())
md = VelocityVerlet(a, dt=0.5 * fs, logfile='-', loginterval=500)
traj = PickleTrajectory('4N.traj', 'w', a)
md.attach(traj.write, 100)
e0 = a.get_total_energy()
md.run(steps=10000)
del traj
assert abs(read('4N.traj').get_total_energy() - e0) < 0.0001
qn = QuasiNewton(a)
qn.run(0.001)
assert abs(a.get_potential_energy() - 1.0) < 0.000002
from ase_ext import Atoms
from ase_ext.calculators.emt import EMT
h2 = Atoms('H2', positions=[(0, 0, 0), (0, 0, 1.1)], calculator=EMT())
print(h2.calc.get_numeric_forces(h2))
print(h2.get_forces())