def test_create_seed_periodic():
system, pars = get_system('cau13')
configuration = Configuration(system, pars)
# change parameters randomly
with pytest.raises(ValueError): # cell is too small
configuration.supercell = [3, 1, 1]
configuration.rcut = 12.0
assert configuration.interaction_radius == 12.0 # should change too
configuration.switch_width = 5.0
configuration.tailcorrections = False
seed_covalent = configuration.create_seed(kind='covalent')
ff = yaff_generate(seed_covalent)
energy_covalent = ff.compute()
seed_dispersion = configuration.create_seed(kind='dispersion')
ff = yaff_generate(seed_dispersion)
energy_dispersion = ff.compute()
seed_electrostatic = configuration.create_seed(kind='electrostatic')
ff = yaff_generate(seed_electrostatic)
energy_electrostatic = ff.compute()
seed_nonbonded = configuration.create_seed(kind='nonbonded')
ff = yaff_generate(seed_nonbonded)
energy_nonbonded = ff.compute()
seed_full = configuration.create_seed(kind='all')
ff = yaff_generate(seed_full)
energy_full = ff.compute()
assert abs(energy_covalent) > 0.0
assert abs(energy_dispersion) > 0.0
assert abs(energy_electrostatic) > 0.0
np.testing.assert_almost_equal(
energy_nonbonded,
energy_dispersion + energy_electrostatic,
)
np.testing.assert_almost_equal(
energy_full,
energy_covalent + energy_nonbonded,
)
def test_wrapper_openmm_mic():
system, pars = get_system('mil53')
configuration = Configuration(system, pars)
kind = 'all'
# YAFF and OpenMM use a different switching function. If it is disabled,
# the results between both are identical up to 6 decimals
configuration.switch_width = 0.0 # disable switching
configuration.rcut = 10.0 # request cutoff of 10 angstorm
configuration.cell_interaction_radius = 10.0
configuration.supercell = [2, 3, 5]
configuration.update_properties(configuration.write())
conversion = ExplicitConversion(pme_error_thres=1e-5)
seed_mm = conversion.apply(configuration, seed_kind=kind)
wrapper = OpenMMForceFieldWrapper.from_seed(seed_mm, 'Reference')
u = molmod.units.angstrom
seed_yaff = configuration.create_seed(kind=kind)
positions = seed_yaff.system.pos.copy() / u
rvecs = seed_yaff.system.cell._get_rvecs().copy() / u
e, _ = wrapper.evaluate(positions, rvecs, do_forces=True)
# make random periodic displacements
for i in range(5):
coefficients = np.random.randint(-3, high=3, size=(3, 1))
atom = np.random.randint(0, high=seed_yaff.system.natom, size=(10,))
positions[atom, :] += np.sum(coefficients * rvecs, axis=0)
e_ = wrapper.evaluate(positions, rvecs, do_forces=False)
assert np.allclose(e, e_)
# make random periodic displacements and rewrap coordinates
for i in range(5):
coefficients = np.random.randint(-3, high=3, size=(3, 1))
atom = np.random.randint(0, high=seed_yaff.system.natom, size=(10,))
positions[atom, :] += np.sum(coefficients * rvecs, axis=0)
wrap_coordinates(positions, rvecs, rectangular=True)
e_ = wrapper.evaluate(positions, rvecs, do_forces=False)
assert np.allclose(e, e_)
def test_topology_templates(tmp_path):
def check_consistency_system_topology(system, topology):
assert system.natom == len(list(topology.atoms()))
for i, atom in zip(range(system.natom), topology.atoms()):
assert system.numbers[i] == atom.element._atomic_number
assert system.bonds.shape[0] == len(list(topology.bonds()))
bonds_tuples = [tuple(sorted(list(bond))) for bond in system.bonds]
for bond in topology.bonds():
indices_top = tuple(sorted((bond[0].index, bond[1].index)))
bonds_tuples.remove(indices_top)
assert len(bonds_tuples) == 0
system, pars = get_system('methane')
configuration = Configuration(system, pars, topology=None)
assert len(configuration.templates) == 1
assert len(configuration.templates[0]) == 5 # five atoms for CH4 template
nresidues = np.sum([len(r) for r in configuration.residues.values()])
supercell = [3, 1, 2]
configuration.supercell = supercell
top, _ = configuration.create_topology()
assert len(list(top.residues())) == np.prod(supercell) * nresidues
seed = configuration.create_seed()
check_consistency_system_topology(seed.system, top)
system, pars = get_system('uio66')
configuration = Configuration(system, pars, topology=None)
assert len(configuration.templates) == 1
assert len(configuration.templates[0]) == system.natom
supercell = [2, 2, 2]
configuration.supercell = supercell
top, positions = configuration.create_topology()
assert len(list(top.residues())) == np.prod(supercell)
seed = configuration.create_seed()
check_consistency_system_topology(seed.system, top)
assert np.allclose(positions, seed.system.pos / molmod.units.angstrom)
(system, topology), pars = get_system('polymer')
configuration = Configuration(system, pars, topology=topology)
assert len(configuration.templates) == 3
top, positions = configuration.create_topology()
assert len(list(top.residues())) == len(list(topology.residues()))
seed = configuration.create_seed()
check_consistency_system_topology(seed.system, top)
assert np.allclose(positions, seed.system.pos / molmod.units.angstrom)
a, b, c = top.getPeriodicBoxVectors()
box = np.array([
a.value_in_unit(unit.angstrom),
b.value_in_unit(unit.angstrom),
c.value_in_unit(unit.angstrom),
])
assert np.allclose(box, seed.system.cell._get_rvecs() / molmod.units.angstrom)
# test nonperiodic
system, pars = get_system('alanine')
configuration = Configuration(system, pars)
assert len(configuration.templates) == 1
top, positions = configuration.create_topology()
seed = configuration.create_seed()
check_consistency_system_topology(seed.system, top)
assert np.allclose(positions, seed.system.pos / molmod.units.angstrom)