def create_molecular_graph(selected_nodes, parent=None):
molecule = create_molecule(selected_nodes, parent)
atom_indexes = dict((atom, i) for i, atom in enumerate(molecule.atoms))
bonds = list(
bond
for bond in iter_bonds(selected_nodes)
if bond.children[0].target in atom_indexes and bond.children[1].target in atom_indexes
)
pairs = [(atom_indexes[bond.children[0].target], atom_indexes[bond.children[1].target]) for bond in bonds]
graph = MolecularGraph(pairs, molecule.numbers)
graph.bonds = bonds
graph.molecule = molecule
return graph
def __init__(self, dihedral, molecule=None, top_indexes=None, potential=None):
"""
Arguments
| ``dihedral`` -- the index of the atoms that define the dihedral
angle
Optional arguments
| ``molecule`` -- a molecule object. required when top_indexes is not
given
| ``top_indexes`` -- a list of atom indexes involved in the rotor.
required when molecule is not given
| ``potential`` -- rotational potential info (if this is a hindered
rotor). must be a two-tuple containing the angles
and the corresponding energies.
"""
self.dihedral = dihedral
if top_indexes is None:
# try to deduce the top indexes
if molecule is None:
raise ValueError("missing arguemt: top_indexes or molecule from which top_indexes can be derived")
atom0, atom1 = dihedral[1:3]
graph = MolecularGraph.from_geometry(molecule)
half0, half1 = graph.get_halfs(atom0, atom1)
if len(half1) > len(half0):
top_indexes = half0
top_indexes.discard(atom0)
else:
top_indexes = half1
top_indexes.discard(atom1)
top_indexes = tuple(top_indexes)
self.top_indexes = top_indexes
self.potential = potential
def create_molecular_graph(selected_nodes, parent=None):
molecule = create_molecule(selected_nodes, parent)
atom_indexes = dict((atom, i) for i, atom in enumerate(molecule.atoms))
bonds = list(bond for bond in iter_bonds(selected_nodes)
if bond.children[0].target in atom_indexes
and bond.children[1].target in atom_indexes)
pairs = [(
atom_indexes[bond.children[0].target],
atom_indexes[bond.children[1].target],
) for bond in bonds]
graph = MolecularGraph(pairs, molecule.numbers)
graph.bonds = bonds
graph.molecule = molecule
return graph
def __init__(self,
dihedral,
molecule=None,
top_indexes=None,
potential=None):
"""
Arguments
| ``dihedral`` -- the index of the atoms that define the dihedral
angle
Optional arguments
| ``molecule`` -- a molecule object. required when top_indexes is not
given
| ``top_indexes`` -- a list of atom indexes involved in the rotor.
required when molecule is not given or when the
top_indexes can not be derived automatically.
| ``potential`` -- rotational potential info (if this is a hindered
rotor). must be a two-tuple containing the angles
and the corresponding energies.
"""
self.dihedral = dihedral
if top_indexes is None:
# try to deduce the top indexes
if molecule is None:
raise ValueError(
"missing arguemt: top_indexes or molecule from which top_indexes can be derived"
)
atom0, atom1 = dihedral[1:3]
graph = MolecularGraph.from_geometry(molecule)
half0, half1 = graph.get_halfs(atom0, atom1)
if (len(half0) + len(half1) !=
molecule.size) or len(half0) == 1 or len(half1) == 1:
raise ValueError(
"The rotating top could not be assigned properly. Specify the top_indexes manually."
)
if len(half1) > len(half0):
top_indexes = half0
top_indexes.discard(atom0)
else:
top_indexes = half1
top_indexes.discard(atom1)
top_indexes = tuple(top_indexes)
else:
# check the sanity of the top indexes
if not ((self.dihedral[0] in top_indexes) ^
(self.dihedral[3] in top_indexes)):
raise ValueError(
'The top must contain either first or the last atom of the dihedral angle.'
)
if ((self.dihedral[1] in top_indexes) |
(self.dihedral[2] in top_indexes)):
raise ValueError(
'The top may not contain atoms from the central bond of the dihedral angle.'
)
self.top_indexes = top_indexes
self.potential = potential
def test_bias_pathdeviation_mof5():
# Load the system
fn_system = pkg_resources.resource_filename(
__name__, '../../data/test/system_mof5.chk')
system = System.from_file(fn_system)
# Groups that define the COM
atypes = set(
['C_B', 'C_B_BR_O', 'O_p', 'B_p', 'C_HTTP', 'C_O_BR_O', 'C_O'])
graph = MolecularGraph(system.bonds, system.numbers)
indices = graph.independent_vertices
groups = []
for layer in [0, 1]:
groups.append([
iatom for iatom in indices[layer]
if system.get_ffatype(iatom) in atypes
])
# Collective Variables
cv0 = CVCOMProjection(system, groups, 0)
cv1 = CVCOMProjection(system, groups, 1)
# The path, rather random nonsense
# This potential has a discontinuous derivative when there is a jump from
# one nearest point on the path to the next. This can lead to failure of
# the check_gpos_part and check_vtens_part tests when such a jump occurs
# in the finite difference approximation. We avoid this by taking a rather
# coarse path, so we are always close to the same point of the path.
npoints = 20
path = np.zeros((npoints, 3))
path[:, 0] = np.cos(np.linspace(0, np.pi, npoints)) * 0.1
path[:, 1] = np.sin(np.linspace(0, np.pi, npoints)) * -0.1
path[:, 2] = 0.2 * path[:, 0] + path[:, 1]**2
# Test without the harmonic restraint
bias = PathDeviationBias([cv0, cv1], path, 0.0)
part = ForcePartBias(system)
part.add_term(bias)
check_gpos_part(system, part)
check_vtens_part(system, part)
# Test without the harmonic restraint, closest point on path is starting
# point of the path
bias = PathDeviationBias([cv0, cv1], path[5:], 0.0)
index, _, _ = bias.find_nearest_point(
np.array([cv.compute() for cv in bias.cvs]))
assert index == 0
part = ForcePartBias(system)
part.add_term(bias)
check_gpos_part(system, part)
check_vtens_part(system, part)
# Test with the harmonic restraint
bias = PathDeviationBias([cv0, cv1], path, 0.5)
part = ForcePartBias(system)
part.add_term(bias)
check_gpos_part(system, part)
check_vtens_part(system, part)
def get_precursor_model():
m = XYZFile("test/input/mfi_precursor.xyz").get_molecule()
mgraph = MolecularGraph.from_geometry(m)
connect_masks = np.array([
number == 8 and len(mgraph.neighbors[index]) == 1
for index, number in enumerate(m.numbers)
], bool)
radii = np.array([
periodic[number].vdw_radius * {True: 0.3, False: 1.0}[connect_mask]
for number, connect_mask in zip(m.numbers, connect_masks)
], float)
radii += np.random.uniform(0, 0.1, radii.shape)
return m.coordinates, connect_masks, radii
def collect_molecules(self, parent, universe=None):
Atom = context.application.plugins.get_node("Atom")
Bond = context.application.plugins.get_node("Bond")
Frame = context.application.plugins.get_node("Frame")
if universe==None:
universe = parent
atom_to_index = {}
atoms_extra = {}
counter = 0
numbers = []
coordinates = []
for child in parent.children:
if isinstance(child, Atom):
atom_to_index[child] = counter
if len(child.extra) > 0:
atoms_extra[counter] = child.extra
counter += 1
numbers.append(child.number)
coordinates.append(child.get_frame_relative_to(universe).t)
if len(numbers) > 0:
molecule = Molecule(numbers, coordinates, parent.name)
molecule.extra = parent.extra
molecule.atoms_extra = atoms_extra
molecule.bonds_extra = {}
pairs = set([])
for child in parent.children:
if isinstance(child, Bond):
atoms = child.get_targets()
pair = frozenset([atom_to_index[atoms[0]], atom_to_index[atoms[1]]])
if len(child.extra) > 0:
molecule.bonds_extra[pair] = child.extra
pairs.add(pair)
if len(pairs) > 0:
molecule.graph = MolecularGraph(pairs, molecule.numbers)
else:
molecule.graph = None
result = [molecule]
else:
result = []
for child in parent.children:
if isinstance(child, Frame):
result.extend(self.collect_molecules(child, universe))
return result
def __init__(self, dihedral, molecule=None, top_indexes=None, potential=None):
"""
Arguments
| ``dihedral`` -- the index of the atoms that define the dihedral
angle
Optional arguments
| ``molecule`` -- a molecule object. required when top_indexes is not
given
| ``top_indexes`` -- a list of atom indexes involved in the rotor.
required when molecule is not given or when the
top_indexes can not be derived automatically.
| ``potential`` -- rotational potential info (if this is a hindered
rotor). must be a two-tuple containing the angles
and the corresponding energies.
"""
self.dihedral = dihedral
if top_indexes is None:
# try to deduce the top indexes
if molecule is None:
raise ValueError("missing arguemt: top_indexes or molecule from which top_indexes can be derived")
atom0, atom1 = dihedral[1:3]
graph = MolecularGraph.from_geometry(molecule)
half0, half1 = graph.get_halfs(atom0, atom1)
if (len(half0) + len(half1) != molecule.size) or len(half0) == 1 or len(half1) == 1:
raise ValueError("The rotating top could not be assigned properly. Specify the top_indexes manually.")
if len(half1) > len(half0):
top_indexes = half0
top_indexes.discard(atom0)
else:
top_indexes = half1
top_indexes.discard(atom1)
top_indexes = tuple(top_indexes)
else:
# check the sanity of the top indexes
if not ((self.dihedral[0] in top_indexes) ^ (self.dihedral[3] in top_indexes)):
raise ValueError('The top must contain either first or the last atom of the dihedral angle.')
if ((self.dihedral[1] in top_indexes) | (self.dihedral[2] in top_indexes)):
raise ValueError('The top may not contain atoms from the central bond of the dihedral angle.')
self.top_indexes = top_indexes
self.potential = potential
def read_from_file(cls, filename):
"""Construct a Molecule object from a previously saved checkpoint file
Arguments:
| ``filename`` -- the file to load from
Usage::
>>> mol = Molecule.read_from_file("mol.chk")
"""
from tamkin.io.internal import load_chk
# load the file
data = load_chk(filename)
# check the names of the fields:
mandatory_fields = set([
"numbers", "coordinates", "masses", "energy", "gradient", "hessian"
])
if not set(data.iterkeys()).issuperset(mandatory_fields):
raise IOError(
"The Checkpoint file does not contain the mandatory fields.")
# take the mandatory fields
constructor_args = {}
for mfield in mandatory_fields:
constructor_args[mfield] = data[mfield]
# take the optional arguments if present
opt_fields = [
"multiplicity", "symmetry_number", "periodic", "title", "symbols"
]
for ofield in opt_fields:
if ofield in data:
constructor_args[ofield] = data[ofield]
# take the special optional arguments that need conversion
if "edges" in data:
graph = MolecularGraph(data["edges"], data["numbers"])
constructor_args["graph"] = graph
if "cell_vectors" in data:
unit_cell = UnitCell(data["cell_vectors"], data.get("cell_active"))
constructor_args["unit_cell"] = unit_cell
# construct the molecule object
return Molecule(**constructor_args)
def test_cvcomprojection_mof5():
# Load the system
fn_system = pkg_resources.resource_filename(
__name__, '../../data/test/system_mof5.chk')
system = System.from_file(fn_system)
# Groups that define the COM
atypes = set(
['C_B', 'C_B_BR_O', 'O_p', 'B_p', 'C_HTTP', 'C_O_BR_O', 'C_O'])
graph = MolecularGraph(system.bonds, system.numbers)
indices = graph.independent_vertices
groups = []
for layer in [0, 1]:
groups.append([
iatom for iatom in indices[layer]
if system.get_ffatype(iatom) in atypes
])
# Compute the COMs explicitly
coms = [(system.pos[group] * system.masses[group].reshape(
(-1, 1))).sum(axis=0) / system.masses[group].sum() for group in groups]
relcom = coms[1] - coms[0]
# Loop over different projections
for index in range(3):
# Compute using the CollectiveVariable
cv = CVCOMProjection(system, groups, index)
value = cv.compute()
# Compute the projection vector
a, b, c = system.cell.rvecs[0], system.cell.rvecs[
1], system.cell.rvecs[2]
if index == 0:
u = a.copy()
elif index == 1:
u = np.cross(np.cross(a, b), a)
elif index == 2:
u = np.cross(a, b)
u /= np.linalg.norm(u)
cv_ref = np.dot(relcom, u)
assert np.abs(cv_ref - value) < 1e-3
# Check derivatives
check_gpos_cv_fd(cv)
check_vtens_cv_fd(cv)
