from molsysmt._private.argdigest import arg_digest
from molsysmt._private.smonitor import StructuralInconsistencyError
from smonitor import signal
[docs]
@signal(tags=['api', 'structure'])
@arg_digest()
def append_structures(to_molecular_system, from_molecular_system, selection='all',
structure_indices='all', syntax='MolSysMT', in_place=True,
attribute_policy='intersection', skip_digestion=False):
"""
Appending structures from one molecular system into another.
This function appends structural information (coordinates, box dimensions, velocities, etc.)
from a source molecular system (`from_molecular_system`) into a target molecular system
(`to_molecular_system`). The result is a molecular system with additional structures
(frames or conformations).
The appended structures must correspond to the same number and ordering of atoms as the
target system. The source does not need to provide topology; coordinate-only forms such as
XTC, DCD, and XYZ are accepted. If the number of atoms differs, a selection of atoms from
the source system must be provided using the `selection` argument. Matching atom ordering
is the caller's responsibility when the source has no topology.
By default, the operation modifies the input molecular system in place. This behavior can be
changed by setting `in_place=False`, in which case a new molecular system is returned.
Parameters
----------
to_molecular_system : molecular system
Molecular system that will receive the new structures. Must be in one of
:ref:`the supported forms <Introduction_Forms>`.
from_molecular_system : molecular system
Molecular system providing the structures to append. Must be in one of
:ref:`the supported forms <Introduction_Forms>`.
selection : str, list, tuple or numpy.ndarray, default 'all'
Selection of atoms from the source system whose structural attributes
will be appended. Can be a list/array of 0-based atom indices, or a string using
any of the supported selection syntaxes (:ref:`Introduction_Selection`).
Only needed when the number of atoms differs between systems.
structure_indices : int, list, tuple, numpy.ndarray or 'all', default 'all'
0-based indices of the structures in the source system to append.
syntax : str, default 'MolSysMT'
Selection syntax used if `selection` is a string. Must be one of the
supported syntaxes in :ref:`Introduction_Selection`.
in_place : bool, default True
If True, modifies `to_molecular_system` directly. If False, returns a new
molecular system with the appended structures, leaving the original unmodified.
attribute_policy : {'intersection', 'strict'}, default 'intersection'
Policy for structural attributes present in only one block. ``'intersection'``
discards one-sided series with a warning; ``'strict'`` rejects the operation.
skip_digestion : bool, default False
Whether to skip MolSysMT’s internal argument digestion mechanism. Use with caution.
Returns
-------
molecular system or None
If `in_place=True`, returns `None` and modifies `to_molecular_system` directly.
If `in_place=False`, returns a new molecular system (same form as the input) with the appended structures.
Raises
------
NotSupportedFormError
If either molecular system is not provided in a supported form.
StructuralInconsistencyError
If atom counts differ, structural axes are inconsistent, or strict policy
rejects one-sided attributes.
SyntaxError
If the selection syntax is not recognized.
Notes
-----
- All forms listed in :ref:`Introduction_Forms` are accepted for both source and target systems.
- Selection strings must follow one of the syntaxes described in
:ref:`Introduction_Selection`.
- Source topology is optional. Atom-count compatibility is always required, while chemical
identity is not inferred from coordinates alone.
- A target with one chemical state associates new structures with that state implicitly.
Multi-state targets preserve explicit source associations when inventories match and use
an unknown association only when the incoming state cannot be determined.
See Also
--------
:func:`molsysmt.basic.select` :
Select atoms from a molecular system.
:func:`molsysmt.basic.concatenate_structures` :
Concatenate structures from multiple molecular systems into one.
:func:`molsysmt.basic.add` :
Adding elements from one molecular system into another.
:func:`molsysmt.basic.merge` :
Merge multiple molecular systems into one.
Examples
--------
>>> import molsysmt as msm
>>> from molsysmt import systems
>>> molsys_A = msm.convert(systems['alanine dipeptide']['alanine_dipeptide.h5msm'])
>>> molsys_B = msm.structure.translate(molsys_A, translation='[0.1, 0.1, 0.1] nanometers')
>>> msm.get(molsys_A, n_structures=True)
1
>>> msm.append_structures(molsys_A, molsys_B)
>>> msm.get(molsys_A, n_structures=True)
2
.. admonition:: Tutorial with more examples
See the following tutorial for a practical demonstration of how to use this function,
along with additional examples: :ref:`Tutorial_Append_structures`.
.. versionadded:: 1.0.0
"""
from . import get_form, extract, get, copy
from molsysmt.form import _dict_modules
if not in_place:
to_molecular_system = copy(to_molecular_system)
_input_was_sequence = isinstance(to_molecular_system, (list, tuple))
if not _input_was_sequence:
to_molecular_system = [to_molecular_system]
to_forms = get_form(to_molecular_system)
from_form = get_form(from_molecular_system)
coordinates, velocities, b_factor, occupancy, alternate_location = get(
from_molecular_system,
element='atom',
selection=selection,
syntax=syntax,
structure_indices=structure_indices,
coordinates=True,
velocities=True,
b_factor=True,
occupancy=True,
alternate_location=True,
skip_digestion=True,
)
(
structure_id,
time,
box,
temperature,
potential_energy,
kinetic_energy,
) = get(
from_molecular_system,
element='system',
structure_indices=structure_indices,
syntax=syntax,
structure_id=True,
time=True,
box=True,
temperature=True,
potential_energy=True,
kinetic_energy=True,
skip_digestion=True,
)
if coordinates is not None:
n_source_atoms = coordinates.shape[1]
elif velocities is not None:
n_source_atoms = velocities.shape[1]
else:
atom_indices = get(
from_molecular_system,
element='atom',
selection=selection,
syntax=syntax,
atom_index=True,
skip_digestion=True,
)
n_source_atoms = len(atom_indices)
for aux_to_item, aux_to_form in zip(to_molecular_system, to_forms):
n_target_atoms = get(
aux_to_item,
element='system',
n_atoms=True,
skip_digestion=True,
)
if n_source_atoms != n_target_atoms:
raise StructuralInconsistencyError(
reason=(
f"Selected source atoms ({n_source_atoms}) do not match target "
f"n_atoms ({n_target_atoms}). Adjust `selection` or ensure the "
"source structures use the target atom ordering."
),
caller='molsysmt.basic.append_structures',
)
if aux_to_form == 'molsysmt.MolSys' and from_form == 'molsysmt.MolSys':
source = extract(
from_molecular_system,
selection=selection,
structure_indices=structure_indices,
syntax=syntax,
to_form='molsysmt.MolSys',
skip_digestion=True,
)
aux_to_item.append_structures(
source,
attribute_policy=attribute_policy,
skip_digestion=True,
)
continue
kwargs = {
'structure_id': structure_id,
'time': time,
'coordinates': coordinates,
'box': box,
'velocities': velocities,
}
if aux_to_form in {
'molsysmt.MolSys',
'molsysmt.Structures',
'molsysmt.StructuresDict',
}:
kwargs.update({
'temperature': temperature,
'potential_energy': potential_energy,
'kinetic_energy': kinetic_energy,
'b_factor': b_factor,
'alternate_location': alternate_location,
'occupancy': occupancy,
'attribute_policy': attribute_policy,
})
_dict_modules[aux_to_form].append_structures(aux_to_item, **kwargs)
if not in_place:
return to_molecular_system if _input_was_sequence else to_molecular_system[0]
else:
pass
