import ctypes
import io
import pathlib
from pickle import PickleBuffer
from typing import BinaryIO, List, Optional, Sequence, Tuple, Union, overload
import numpy as np
from ._c_api import c_uintptr_t, mts_labels_t
from ._c_lib import _get_library
from .utils import _ptr_to_const_ndarray
[docs]
class LabelsValues(np.ndarray):
"""
Wrapper class around the values inside :py:class:`Labels`, keeping a reference to
the :py:class:`Labels` alive as needed. This class inherit from
:py:class:`numpy.ndarray`, and can be used anywhere a numpy ndarray can be used.
"""
def __new__(cls, labels: "Labels"):
array = _ptr_to_const_ndarray(
ptr=labels._labels.values,
shape=(labels._labels.count, labels._labels.size),
dtype=np.int32,
)
obj = array.view(cls)
# keep a reference to the Python labels to prevent them from being
# garbage-collected too early.
obj._parent = labels
return obj
def __array_finalize__(self, obj):
# keep the parent around when creating sub-views of this array
self._parent = getattr(obj, "_parent", None)
def __array_wrap__(self, new, context=None, return_scalar=False):
self_ptr = self.ctypes.data
self_size = self.nbytes
new_ptr = new.ctypes.data
if self_ptr <= new_ptr <= self_ptr + self_size:
# if the new array is a view inside memory owned by self, wrap it in
# LabelsValues
return super().__array_wrap__(new)
else:
# otherwise return the ndarray straight away
return np.asarray(new)
[docs]
class LabelsEntry:
"""A single entry (i.e. row) in a set of :py:class:`Labels`.
The main way to create a :py:class:`LabelsEntry` is to index a
:py:class:`Labels` or iterate over them.
>>> from metatensor import Labels
>>> import numpy as np
>>> labels = Labels(
... names=["system", "atom", "center_type"],
... values=np.array([(0, 1, 8), (0, 2, 1), (0, 5, 1)]),
... )
>>> entry = labels[0] # or labels.entry(0)
>>> entry.names
['system', 'atom', 'center_type']
>>> print(entry.values)
[0 1 8]
"""
def __init__(self, names: List[str], values: LabelsValues):
assert isinstance(names, list)
for n in names:
assert isinstance(n, str)
assert isinstance(values, LabelsValues)
self._names = names
if len(values.shape) != 1 or values.dtype != np.int32:
raise ValueError(
"LabelsEntry values must be a 1-dimensional array of 32-bit integers"
)
self._values = values
@property
def names(self) -> List[str]:
"""names of the dimensions for this Labels entry"""
return self._names
@property
def values(self) -> LabelsValues:
"""
values associated with each dimensions of this Labels entry, stored as
32-bit integers.
"""
return self._values
@property
def device(self) -> str:
"""
Get the device of this labels entry.
This exists for compatibility with the TorchScript API, and always returns
``"cpu"`` when called.
"""
return "cpu"
[docs]
def print(self) -> str:
"""
print this entry as a named tuple (i.e. ``(key_1=value_1, key_2=value_2)``)
"""
values = [f"{n}={v}" for n, v in zip(self.names, self.values)]
return f"({', '.join(values)})"
def __repr__(self) -> str:
return "LabelsEntry" + self.print()
def __len__(self) -> int:
"""number of dimensions in this labels entry"""
return self._values.shape[0]
def __getitem__(self, dimension: Union[str, int]) -> int:
"""get the value associated with the dimension in this entry"""
if isinstance(dimension, int):
return self._values[dimension]
elif isinstance(dimension, str):
try:
i = self._names.index(dimension)
except ValueError:
raise ValueError(
f"'{dimension}' not found in the dimensions of these Labels"
)
return self._values[i]
else:
raise TypeError(
f"can only index LabelsEntry with str or int, got {type(dimension)}"
)
def __eq__(self, other: "LabelsEntry") -> bool:
"""
check if ``self`` and ``other`` are equal (same dimensions/names and
same values)
"""
if not isinstance(other, LabelsEntry):
raise TypeError(
f"can only compare between LabelsEntry for equality, got {type(other)}"
)
return (
self._names == other._names
and self._values.shape == other._values.shape
and np.all(self._values == other._values)
)
def __ne__(self, other: "LabelsEntry") -> bool:
"""
check if ``self`` and ``other`` are not equal (different
dimensions/names or different values)
"""
return not self.__eq__(other)
[docs]
class Labels:
"""
A set of labels carrying metadata associated with a :py:class:`TensorMap`.
The metadata can be though as a list of tuples, where each value in the
tuple also has an associated dimension name. In practice, the dimensions
``names`` are stored separately from the ``values``, and the values are in a
2-dimensional array integers with the shape ``(n_entries, n_dimensions)``.
Each row/entry in this array is unique, and they are often (but not always)
sorted in lexicographic order.
>>> from metatensor import Labels
>>> import numpy as np
>>> labels = Labels(
... names=["system", "atom", "center_type"],
... values=np.array([(0, 1, 8), (0, 2, 1), (0, 5, 1)]),
... )
>>> labels
Labels(
system atom center_type
0 1 8
0 2 1
0 5 1
)
>>> labels.names
['system', 'atom', 'center_type']
>>> print(labels.values)
[[0 1 8]
[0 2 1]
[0 5 1]]
It is possible to create a view inside a :py:class:`Labels`, selecting a subset of
columns/dimensions:
>>> # single dimension
>>> view = labels.view("atom")
>>> view.names
['atom']
>>> print(view.values)
[[1]
[2]
[5]]
>>> # multiple dimensions
>>> view = labels.view(["atom", "system"])
>>> view.names
['atom', 'system']
>>> print(view.values)
[[1 0]
[2 0]
[5 0]]
>>> view.is_view()
True
>>> # we can convert a view back to a full, owned Labels
>>> owned_labels = view.to_owned()
>>> owned_labels.is_view()
False
One can also iterate over labels entries, or directly index the :py:class:`Labels`
to get a specific entry
>>> entry = labels[0] # or labels.entry(0)
>>> entry.names
['system', 'atom', 'center_type']
>>> print(entry.values)
[0 1 8]
>>> for entry in labels:
... print(entry)
...
LabelsEntry(system=0, atom=1, center_type=8)
LabelsEntry(system=0, atom=2, center_type=1)
LabelsEntry(system=0, atom=5, center_type=1)
Or get all the values associated with a given dimension/column name
>>> print(labels.column("atom"))
[1 2 5]
>>> print(labels["atom"]) # alternative syntax for the above
[1 2 5]
Labels can be checked for equality:
>>> owned_labels == labels
False
>>> labels == labels
True
Finally, it is possible to check if a value is inside (non-view) labels, and
get the corresponding position:
>>> labels.position([0, 2, 1])
1
>>> print(labels.position([0, 2, 4]))
None
>>> (0, 2, 4) in labels
False
>>> labels[2] in labels
True
"""
def __init__(self, names: Union[str, Sequence[str]], values: np.ndarray):
"""
:param names: names of the dimensions in the new labels. A single string
is transformed into a list with one element, i.e.
``names="a"`` is the same as ``names=["a"]``.
:param values: values of the labels, this needs to be a 2-dimensional
array of integers.
"""
names = _normalize_names_type(names)
if not isinstance(values, np.ndarray):
raise ValueError("`values` must be a numpy ndarray")
if len(values) == 0:
# make sure the array is 2D
values = np.zeros((0, len(names)), dtype=np.int32)
elif len(values.shape) != 2:
raise ValueError("`values` must be a 2D array")
if len(names) != values.shape[1]:
raise ValueError(
"`names` must have an entry for each column of the `values` array"
)
try:
# We need to make sure the data is C-contiguous to take a pointer to
# it, and that it has the right type
values = np.ascontiguousarray(
values.astype(
np.int32,
order="C",
casting="same_kind",
subok=False,
copy=False,
)
)
except TypeError as e:
raise TypeError("Labels values must be convertible to integers") from e
self._lib = _get_library()
self._labels = _create_new_labels(self._lib, names, values)
self._names = names
self._values = LabelsValues(self)
[docs]
@staticmethod
def single() -> "Labels":
"""
Create :py:class:`Labels` to use when there is no relevant metadata and
only one entry in the corresponding dimension (e.g. keys when a tensor
map contains a single block).
"""
return Labels(names=["_"], values=np.zeros(shape=(1, 1), dtype=np.int32))
[docs]
@staticmethod
def empty(names: Union[str, Sequence[str]]) -> "Labels":
"""
Create :py:class:`Labels` with given ``names`` but no values.
:param names: names of the dimensions in the new labels. A single string
is transformed into a list with one element, i.e.
``names="a"`` is the same as ``names=["a"]``.
"""
return Labels(names=names, values=np.array([]))
[docs]
@staticmethod
def range(name: str, end: int) -> "Labels":
"""
Create :py:class:`Labels` with a single dimension using the given
``name`` and values in the ``[0, end)`` range.
:param name: name of the single dimension in the new labels.
:param end: end of the range for labels
>>> from metatensor import Labels
>>> labels = Labels.range("dummy", 7)
>>> labels.names
['dummy']
>>> print(labels.values)
[[0]
[1]
[2]
[3]
[4]
[5]
[6]]
"""
return Labels(
names=[name],
values=np.arange(end, dtype=np.int32).reshape(-1, 1),
)
@classmethod
def _from_mts_labels_t(cls, labels: mts_labels_t):
assert labels.internal_ptr_ is not None
obj = cls.__new__(cls)
obj._lib = _get_library()
obj._labels = labels
names = []
for i in range(labels.size):
names.append(labels.names[i].decode("utf8"))
obj._names = names
obj._values = LabelsValues(obj)
return obj
def __del__(self):
if hasattr(self, "_lib") and self._lib is not None:
if hasattr(self, "_labels") and self._labels is not None:
self._lib.mts_labels_free(self._labels)
def __deepcopy__(self, _memodict):
labels = mts_labels_t()
self._lib.mts_labels_clone(self._labels, labels)
return Labels._from_mts_labels_t(labels)
def __copy__(self):
return self.__deepcopy__({})
def __str__(self) -> str:
printed = self.print(4, 3)
if self.is_view():
return f"LabelsView(\n {printed}\n)"
else:
return f"Labels(\n {printed}\n)"
def __repr__(self) -> str:
printed = self.print(-1, 3)
if self.is_view():
return f"LabelsView(\n {printed}\n)"
else:
return f"Labels(\n {printed}\n)"
def __len__(self) -> int:
"""number of entries in these labels"""
return self._values.shape[0]
def __iter__(self):
for i in range(len(self)):
yield LabelsEntry(self._names, self._values[i, :])
@overload
def __getitem__(self, dimension: str) -> np.ndarray:
pass
@overload
def __getitem__(self, index: int) -> LabelsEntry:
pass
def __getitem__(self, index):
"""
When indexing with a string, get the values for the corresponding dimension as a
1-dimensional array (i.e. :py:func:`Labels.column`).
When indexing with an integer, get the corresponding row/labels entry (i.e.
:py:func:`Labels.entry`).
See also :py:func:`Labels.view` to extract the values associated with multiple
columns/dimensions.
"""
if isinstance(index, (int, np.int8, np.int16, np.int32, np.int64)):
return self.entry(index)
else:
return self.column(index)
def __contains__(
self,
entry: Union[LabelsEntry, Sequence[int]],
) -> bool:
"""check if these :py:class:`Labels` contain the given ``entry``"""
if self.is_view():
raise ValueError(
"can not call `__contains__` on a Labels view, call `to_owned` before"
)
return self.position(entry) is not None
def __eq__(self, other: "Labels") -> bool:
"""
check if two set of labels are equal (same dimension names and same
values)
"""
if not isinstance(other, Labels):
raise TypeError(
f"can only compare between Labels for equality, got {type(other)}"
)
return (
self._names == other._names
and self._values.shape == other._values.shape
and np.all(self._values == other._values)
)
def __ne__(self, other: "Labels") -> bool:
"""
check if two set of labels are not equal (different dimension names or
different values)
"""
return not self.__eq__(other)
def _as_mts_labels_t(self):
if self.is_view():
raise ValueError(
"can not use a Labels view with the metatensor shared library, "
"call `to_owned` before"
)
else:
return self._labels
# ===== Serialization support ===== #
@classmethod
def _from_pickle(cls, buffer: Union[bytes, bytearray]):
"""
Passed to pickler to reconstruct Labels from bytes object
"""
from .io import load_labels_buffer
return load_labels_buffer(buffer)
def __reduce_ex__(self, protocol: int):
"""
Used by the Pickler to dump Labels object to bytes object. When protocol >= 5
it supports PickleBuffer which reduces number of copies needed
"""
from .io import _save_labels_buffer_raw
buffer = _save_labels_buffer_raw(self)
if protocol >= 5:
return self._from_pickle, (PickleBuffer(buffer),)
else:
return self._from_pickle, (buffer.raw,)
[docs]
@staticmethod
def load(file: Union[str, pathlib.Path, BinaryIO]) -> "Labels":
"""
Load a serialized :py:class:`Labels` from a file, calling
:py:func:`metatensor.load_labels`.
:param file: file path or file object to load from
"""
from .io import load_labels
return load_labels(file=file)
[docs]
@staticmethod
def load_buffer(buffer: Union[bytes, bytearray, memoryview]) -> "Labels":
"""
Load a serialized :py:class:`Labels` from a buffer, calling
:py:func:`metatensor.io.load_labels_buffer`.
:param buffer: in-memory buffer containing the data
"""
from .io import load_labels_buffer
return load_labels_buffer(buffer=buffer)
[docs]
def save(self, file: Union[str, pathlib.Path, BinaryIO]):
"""
Save these :py:class:`Labels` to a file, calling :py:func:`metatensor.save`.
:param file: file path or file object to save to
"""
from .io import save
return save(file=file, data=self)
[docs]
def save_buffer(self) -> memoryview:
"""
Save these :py:class:`Labels` to an in-memory buffer, calling
:py:func:`metatensor.io.save_buffer`.
"""
from .io import save_buffer
return save_buffer(data=self)
# ===== Data manipulation ===== #
@property
def names(self) -> List[str]:
"""names of the dimensions for these :py:class:`Labels`"""
return self._names
@property
def values(self) -> np.ndarray:
"""
values associated with each dimensions of the :py:class:`Labels`, stored
as 2-dimensional tensor of 32-bit integers
"""
return self._values
[docs]
def append(self, name: str, values: np.ndarray) -> "Labels":
"""Append a new dimension to the end of the :py:class:`Labels`.
:param name: name of the new dimension
:param values: 1D array of values for the new dimension
>>> import numpy as np
>>> from metatensor import Labels
>>> label = Labels("foo", np.array([[42]]))
>>> label
Labels(
foo
42
)
>>> label.append(name="bar", values=np.array([10]))
Labels(
foo bar
42 10
)
"""
return self.insert(index=len(self), name=name, values=values)
[docs]
def insert(self, index: int, name: str, values: np.ndarray) -> "Labels":
"""Insert a new dimension before ``index`` in the :py:class:`Labels`.
:param index: index before the new dimension is inserted
:param name: name of the new dimension
:param values: 1D array of values for the new dimension
>>> import numpy as np
>>> from metatensor import Labels
>>> label = Labels("foo", np.array([[42]]))
>>> label
Labels(
foo
42
)
>>> label.insert(0, name="bar", values=np.array([10]))
Labels(
bar foo
10 42
)
"""
new_names = self.names.copy()
new_names.insert(index, name)
if not isinstance(values, np.ndarray):
raise ValueError("`values` must be a numpy ndarray")
if len(values.shape) != 1:
raise ValueError("`values` must be a 1D array")
if values.shape[0] != len(self):
raise ValueError(
f"the new `values` contains {values.shape[0]} entries, "
f"but the Labels contains {len(self)}"
)
new_values = np.insert(self.values, index, values, axis=1)
return Labels(names=new_names, values=new_values)
[docs]
def permute(self, dimensions_indexes: List[int]) -> "Labels":
"""Permute dimensions according to ``dimensions_indexes`` in the
:py:class:`Labels`.
:param dimensions_indexes: desired ordering of the dimensions
:raises ValueError: if length of ``dimensions_indexes`` does not match the
Labels length
:raises ValueError: if duplicate values are present in ``dimensions_indexes``
>>> import numpy as np
>>> from metatensor import Labels
>>> label = Labels(["foo", "bar", "baz"], np.array([[42, 10, 3]]))
>>> label
Labels(
foo bar baz
42 10 3
)
>>> label.permute([2, 0, 1])
Labels(
baz foo bar
3 42 10
)
"""
if len(dimensions_indexes) != len(self.names):
raise ValueError(
f"the length of `dimensions_indexes` ({len(dimensions_indexes)}) does "
f"not match the number of dimensions in the Labels ({len(self.names)})"
)
names = [self.names[d] for d in dimensions_indexes]
return Labels(names=names, values=self.values[:, dimensions_indexes])
[docs]
def remove(self, name: str) -> "Labels":
"""Remove ``name`` from the dimensions of the :py:class:`Labels`.
Removal can only be performed if the resulting :py:class:`Labels` instance will
be unique.
:param name: name to be removed
:raises ValueError: if the name is not present.
>>> import numpy as np
>>> from metatensor import Labels
>>> label = Labels(["foo", "bar"], np.array([[42, 10]]))
>>> label
Labels(
foo bar
42 10
)
>>> label.remove(name="bar")
Labels(
foo
42
)
If the new :py:class:`Labels` is not unique an error is raised.
>>> from metatensor import MetatensorError
>>> label = Labels(["foo", "bar"], np.array([[42, 10], [42, 11]]))
>>> label
Labels(
foo bar
42 10
42 11
)
>>> try:
... label.remove(name="bar")
... except MetatensorError as e:
... print(e)
...
invalid parameter: can not have the same label value multiple time: [42] is already present at position 0
""" # noqa E501
if name not in self.names:
raise ValueError(f"'{name}' not found in the dimensions of these Labels")
new_names = self.names.copy()
new_names.remove(name)
index = self.names.index(name)
new_values = np.delete(self.values, index, axis=1)
return Labels(names=new_names, values=new_values)
[docs]
def rename(self, old: str, new: str) -> "Labels":
"""Rename the ``old`` dimension to ``new`` in the :py:class:`Labels`.
:param old: name to be replaced
:param new: name after the replacement
:raises ValueError: if old is not present.
>>> import numpy as np
>>> from metatensor import Labels
>>> label = Labels("foo", np.array([[42]]))
>>> label
Labels(
foo
42
)
>>> label.rename("foo", "bar")
Labels(
bar
42
)
"""
if old not in self.names:
raise ValueError(f"'{old}' not found in the dimensions of these Labels")
names = self.names.copy()
index = names.index(old)
names[index] = new
return Labels(names=names, values=self.values)
[docs]
def to(self, device) -> "Labels":
"""
Move the values for these Labels to the given ``device``.
In the Python version of metatensor, this returns the original labels.
Defined for compatibility with the TorchScript version of metatensor.
"""
return self
@property
def device(self) -> str:
"""
Get the device of these Labels.
This exists for compatibility with the TorchScript API, and always returns
``"cpu"`` when called.
"""
return "cpu"
[docs]
def position(self, entry: Union[LabelsEntry, Sequence[int]]) -> Optional[int]:
"""
Get the position of the given ``entry`` in this set of
:py:class:`Labels`, or ``None`` if the entry is not present in the
labels.
"""
if self.is_view():
raise ValueError(
"can not call `position` on a Labels view, call `to_owned` before"
)
result = ctypes.c_int64()
c_entry = ctypes.ARRAY(ctypes.c_int32, len(entry))()
for i, v in enumerate(entry):
c_entry[i] = ctypes.c_int32(v)
self._lib.mts_labels_position(
self._labels,
c_entry,
c_entry._length_,
result,
)
if result.value >= 0:
return result.value
else:
return None
[docs]
def union(self, other: "Labels") -> "Labels":
"""
Take the union of these :py:class:`Labels` with ``other``.
If you want to know where entries in ``self`` and ``other`` ends up in the
union, you can use :py:meth:`Labels.union_and_mapping`.
>>> import numpy as np
>>> from metatensor import Labels
>>> first = Labels(names=["a", "b"], values=np.array([[0, 1], [1, 2], [0, 3]]))
>>> second = Labels(names=["a", "b"], values=np.array([[0, 3], [1, 3], [1, 2]]))
>>> first.union(second)
Labels(
a b
0 1
1 2
0 3
1 3
)
"""
if self.is_view() or other.is_view():
raise ValueError(
"can not call `union` with Labels view, call `to_owned` before"
)
output = mts_labels_t()
self._lib.mts_labels_union(
self._as_mts_labels_t(), other._as_mts_labels_t(), output, None, 0, None, 0
)
return Labels._from_mts_labels_t(output)
[docs]
def union_and_mapping(
self, other: "Labels"
) -> Tuple["Labels", np.ndarray, np.ndarray]:
"""
Take the union of these :py:class:`Labels` with ``other``.
This function also returns the position in the union where each entry of the
input :py:class::`Labels` ended up.
:return: Tuple containing the union, a :py:class:`numpy.ndarray` containing the
position in the union of the entries from ``self``, and a
:py:class:`numpy.ndarray` containing the position in the union of the
entries from ``other``.
>>> import numpy as np
>>> from metatensor import Labels
>>> first = Labels(names=["a", "b"], values=np.array([[0, 1], [1, 2], [0, 3]]))
>>> second = Labels(names=["a", "b"], values=np.array([[0, 3], [1, 3], [1, 2]]))
>>> union, mapping_1, mapping_2 = first.union_and_mapping(second)
>>> union
Labels(
a b
0 1
1 2
0 3
1 3
)
>>> print(mapping_1)
[0 1 2]
>>> print(mapping_2)
[2 3 1]
"""
if self.is_view() or other.is_view():
raise ValueError(
"can not call `union_and_mapping` with Labels view, call `to_owned` "
"before"
)
output = mts_labels_t()
first_mapping = np.zeros(len(self), dtype=np.int64)
second_mapping = np.zeros(len(other), dtype=np.int64)
self._lib.mts_labels_union(
self._as_mts_labels_t(),
other._as_mts_labels_t(),
output,
first_mapping.ctypes.data_as(ctypes.POINTER(ctypes.c_int64)),
len(first_mapping),
second_mapping.ctypes.data_as(ctypes.POINTER(ctypes.c_int64)),
len(second_mapping),
)
return Labels._from_mts_labels_t(output), first_mapping, second_mapping
[docs]
def intersection(self, other: "Labels") -> "Labels":
"""
Take the intersection of these :py:class:`Labels` with ``other``.
If you want to know where entries in ``self`` and ``other`` ends up in the
intersection, you can use :py:meth:`Labels.intersection_and_mapping`.
>>> import numpy as np
>>> from metatensor import Labels
>>> first = Labels(names=["a", "b"], values=np.array([[0, 1], [1, 2], [0, 3]]))
>>> second = Labels(names=["a", "b"], values=np.array([[0, 3], [1, 3], [1, 2]]))
>>> first.intersection(second)
Labels(
a b
1 2
0 3
)
"""
if self.is_view() or other.is_view():
raise ValueError(
"can not call `intersection` with Labels view, call `to_owned` before"
)
output = mts_labels_t()
self._lib.mts_labels_intersection(
self._as_mts_labels_t(), other._as_mts_labels_t(), output, None, 0, None, 0
)
return Labels._from_mts_labels_t(output)
[docs]
def intersection_and_mapping(
self, other: "Labels"
) -> Tuple["Labels", np.ndarray, np.ndarray]:
"""
Take the intersection of these :py:class:`Labels` with ``other``.
This function also returns the position in the intersection where each entry of
the input :py:class:`Labels` ended up.
:return: Tuple containing the intersection, a :py:class:`numpy.ndarray`
containing the position in the intersection of the entries from ``self``,
and a :py:class:`numpy.ndarray` containing the position in the intersection
of the entries from ``other``. If entries in ``self`` or ``other`` are not
used in the output, the mapping for them is set to ``-1``.
>>> import numpy as np
>>> from metatensor import Labels
>>> first = Labels(names=["a", "b"], values=np.array([[0, 1], [1, 2], [0, 3]]))
>>> second = Labels(names=["a", "b"], values=np.array([[0, 3], [1, 3], [1, 2]]))
>>> intersection, mapping_1, mapping_2 = first.intersection_and_mapping(second)
>>> intersection
Labels(
a b
1 2
0 3
)
>>> print(mapping_1)
[-1 0 1]
>>> print(mapping_2)
[ 1 -1 0]
"""
if self.is_view() or other.is_view():
raise ValueError(
"can not call `intersection_and_mapping` with Labels view, call "
"`to_owned` before"
)
output = mts_labels_t()
first_mapping = np.zeros(len(self), dtype=np.int64)
second_mapping = np.zeros(len(other), dtype=np.int64)
self._lib.mts_labels_intersection(
self._as_mts_labels_t(),
other._as_mts_labels_t(),
output,
first_mapping.ctypes.data_as(ctypes.POINTER(ctypes.c_int64)),
len(first_mapping),
second_mapping.ctypes.data_as(ctypes.POINTER(ctypes.c_int64)),
len(second_mapping),
)
return Labels._from_mts_labels_t(output), first_mapping, second_mapping
[docs]
def select(self, selection: "Labels") -> np.ndarray:
"""
Select entries in these :py:class:`Labels` that match the ``selection``.
The selection's names must be a subset of the names of these labels.
All entries in these :py:class:`Labels` that match one of the entry in the
``selection`` for all the selection's dimension will be picked. Any entry in the
``selection`` but not in these :py:class:`Labels` will be ignored.
>>> import numpy as np
>>> from metatensor import Labels
>>> labels = Labels(
... names=["a", "b"],
... values=np.array([[0, 1], [1, 2], [0, 3], [1, 1], [2, 4]]),
... )
>>> selection = Labels(names=["a"], values=np.array([[0], [2], [5]]))
>>> print(labels.select(selection))
[0 2 4]
:param selection: description of the entries to select
:return: 1-dimensional ndarray containing the integer indices of selected
entries
"""
selected = np.zeros((len(self)), dtype=np.int64)
selected_count = c_uintptr_t(len(self))
self._lib.mts_labels_select(
self._as_mts_labels_t(),
selection._as_mts_labels_t(),
selected.ctypes.data_as(ctypes.POINTER(ctypes.c_int64)),
ctypes.pointer(selected_count),
)
selected.resize(selected_count.value, refcheck=False)
return selected
[docs]
def print(self, max_entries: int, indent: int = 0) -> str:
"""print these :py:class:`Labels` to a string
:param max_entries: how many entries to print, use ``-1`` to print everything
:param indent: indent the output by ``indent`` spaces
"""
return _print_labels(
self._names,
self._values,
max_entries=max_entries,
indent=indent,
)
[docs]
def entry(self, index: int) -> LabelsEntry:
"""
Get a single entry/row in these labels.
.. seealso::
:py:func:`Labels.__getitem__` as the main way to use this function
"""
return LabelsEntry(self._names, self._values[index, :])
[docs]
def column(self, dimension: str) -> np.ndarray:
"""
Get the values associated with a single dimension in these labels (i.e. a single
column of :py:attr:`Labels.values`) as a 1-dimensional array.
.. seealso::
:py:func:`Labels.__getitem__` as the main way to use this function
:py:func:`Labels.view` to access multiple columns simultaneously
"""
if not isinstance(dimension, str):
raise TypeError(
f"column names must be a string, got {type(dimension)} instead"
)
try:
index = self.names.index(dimension)
except ValueError:
raise ValueError(
f"'{dimension}' not found in the dimensions of these Labels"
)
return self.values[:, index]
[docs]
def view(self, dimensions: Union[str, Sequence[str]]) -> "Labels":
"""
Get a view for the specified columns in these labels.
.. seealso::
:py:func:`Labels.column` to get the values associated with a single
dimension
"""
names = _normalize_names_type(dimensions)
indices = []
for name in names:
try:
i = self.names.index(name)
indices.append(i)
except ValueError:
raise ValueError(
f"'{name}' not found in the dimensions of these Labels"
)
values = self.values[:, indices]
obj = self.__new__(Labels)
obj._lib = _get_library()
obj._labels = None
obj._names = names
obj._values = values
return obj
[docs]
def is_view(self) -> bool:
"""are these labels a view inside another set of labels?
A view is created with :py:func:`Labels.__getitem__` or
:py:func:`Labels.view`, and does not implement :py:func:`Labels.position`
or :py:func:`Labels.__contains__`.
"""
return self._labels is None
[docs]
def to_owned(self) -> "Labels":
"""convert a view to owned labels, which implement the full API"""
labels = _create_new_labels(self._lib, self._names, self._values)
return Labels._from_mts_labels_t(labels)
def _normalize_names_type(names: Union[str, Sequence[str]]) -> List[str]:
"""
Transform Labels names from any of the accepted types into the canonical
representation (list of strings).
"""
if isinstance(names, str):
if len(names) == 0:
names = []
else:
names = [names]
else:
try:
names = list(names)
except TypeError:
raise TypeError(
f"Labels names must be a sequence of strings, got {type(names)} instead"
)
for name in names:
if not isinstance(name, str):
raise TypeError(
f"Labels names must be strings, got {type(name)} instead"
)
return names
def _create_new_labels(lib, names: List[str], values: np.ndarray) -> mts_labels_t:
labels = mts_labels_t()
c_names = ctypes.ARRAY(ctypes.c_char_p, len(names))()
for i, n in enumerate(names):
c_names[i] = n.encode("utf8")
labels.internal_ptr_ = None
labels.names = c_names
labels.size = len(names)
labels.values = values.ctypes.data_as(ctypes.POINTER(ctypes.c_int32))
labels.count = values.shape[0]
lib.mts_labels_create(labels)
return labels
def _print_string_center(output, string, width, last):
delta = width - len(string)
n_before = delta // 2
n_after = delta - n_before
if last:
# don't add spaces after the last element
output.write(" " * n_before)
output.write(string)
else:
output.write(" " * n_before)
output.write(string)
output.write(" " * n_after)
def _print_labels(
names: List[str],
values: np.ndarray,
max_entries: int,
indent: int,
) -> str:
# ================================================================================ #
# Step 1: determine the width of all the columns (at least the width of the names #
# plus 2, might be wider for large values) #
# ================================================================================ #
# the +2 is here use at least one space on each side of the name
widths = [len(n) + 2 for n in names]
# first set of values to print (before the "...")
values_first = []
# second set of values to print (after the "...")
values_second = []
n_elements = values.shape[0]
# first, determine the width of each column by looking through all the
# values and names lengths
if max_entries < 0 or n_elements <= max_entries:
for entry in values:
entry_strings = []
for i, e in enumerate(entry):
element_str = str(e)
entry_strings.append(element_str)
widths[i] = max(widths[i], len(element_str) + 2)
values_first.append(entry_strings)
else:
if max_entries < 2:
max_entries = 2
n_after = max_entries // 2
n_before = max_entries - n_after
# values before the "..."
for entry in values[:n_before, :]:
entry_strings = []
for i, e in enumerate(entry):
element_str = str(e)
entry_strings.append(element_str)
widths[i] = max(widths[i], len(element_str) + 2)
values_first.append(entry_strings)
# values after the "..."
for entry in values[n_elements - n_after :, :]:
entry_strings = []
for i, e in enumerate(entry):
element_str = str(e)
entry_strings.append(element_str)
widths[i] = max(widths[i], len(element_str) + 2)
values_second.append(entry_strings)
# ================================================================================ #
# Step 2: actually create the output string, using io.StringIO to incrementally #
# append to the output #
# ================================================================================ #
indent_str = " " * indent
n_dimensions = values.shape[1]
output = io.StringIO()
for i in range(n_dimensions):
last = i == n_dimensions - 1
_print_string_center(output, names[i], widths[i], last)
output.write("\n")
for strings in values_first:
output.write(indent_str)
for i in range(n_dimensions):
last = i == n_dimensions - 1
_print_string_center(output, strings[i], widths[i], last)
output.write("\n")
if len(values_second) != 0:
half_header_widths = sum(widths) // 2
if half_header_widths > 3:
# 3 characters in '...'
half_header_widths -= 3
output.write(indent_str)
output.write((half_header_widths + 1) * " ")
output.write("...\n")
for strings in values_second:
output.write(indent_str)
for i in range(n_dimensions):
last = i == n_dimensions - 1
_print_string_center(output, strings[i], widths[i], last)
output.write("\n")
output = output.getvalue()
assert output[-1] == "\n"
return output[:-1]