Updated script that can be controled by Nodejs web app
This commit is contained in:
563
lib/python3.13/site-packages/numpy/lib/_stride_tricks_impl.py
Normal file
563
lib/python3.13/site-packages/numpy/lib/_stride_tricks_impl.py
Normal file
@@ -0,0 +1,563 @@
|
||||
"""
|
||||
Utilities that manipulate strides to achieve desirable effects.
|
||||
|
||||
An explanation of strides can be found in the :ref:`arrays.ndarray`.
|
||||
|
||||
Functions
|
||||
---------
|
||||
|
||||
.. autosummary::
|
||||
:toctree: generated/
|
||||
|
||||
"""
|
||||
import numpy as np
|
||||
from numpy._core.numeric import normalize_axis_tuple
|
||||
from numpy._core.overrides import array_function_dispatch, set_module
|
||||
|
||||
__all__ = ['broadcast_to', 'broadcast_arrays', 'broadcast_shapes']
|
||||
|
||||
|
||||
class DummyArray:
|
||||
"""Dummy object that just exists to hang __array_interface__ dictionaries
|
||||
and possibly keep alive a reference to a base array.
|
||||
"""
|
||||
|
||||
def __init__(self, interface, base=None):
|
||||
self.__array_interface__ = interface
|
||||
self.base = base
|
||||
|
||||
|
||||
def _maybe_view_as_subclass(original_array, new_array):
|
||||
if type(original_array) is not type(new_array):
|
||||
# if input was an ndarray subclass and subclasses were OK,
|
||||
# then view the result as that subclass.
|
||||
new_array = new_array.view(type=type(original_array))
|
||||
# Since we have done something akin to a view from original_array, we
|
||||
# should let the subclass finalize (if it has it implemented, i.e., is
|
||||
# not None).
|
||||
if new_array.__array_finalize__:
|
||||
new_array.__array_finalize__(original_array)
|
||||
return new_array
|
||||
|
||||
|
||||
@set_module("numpy.lib.stride_tricks")
|
||||
def as_strided(x, shape=None, strides=None, subok=False, writeable=True):
|
||||
"""
|
||||
Create a view into the array with the given shape and strides.
|
||||
|
||||
.. warning:: This function has to be used with extreme care, see notes.
|
||||
|
||||
Parameters
|
||||
----------
|
||||
x : ndarray
|
||||
Array to create a new.
|
||||
shape : sequence of int, optional
|
||||
The shape of the new array. Defaults to ``x.shape``.
|
||||
strides : sequence of int, optional
|
||||
The strides of the new array. Defaults to ``x.strides``.
|
||||
subok : bool, optional
|
||||
.. versionadded:: 1.10
|
||||
|
||||
If True, subclasses are preserved.
|
||||
writeable : bool, optional
|
||||
.. versionadded:: 1.12
|
||||
|
||||
If set to False, the returned array will always be readonly.
|
||||
Otherwise it will be writable if the original array was. It
|
||||
is advisable to set this to False if possible (see Notes).
|
||||
|
||||
Returns
|
||||
-------
|
||||
view : ndarray
|
||||
|
||||
See also
|
||||
--------
|
||||
broadcast_to : broadcast an array to a given shape.
|
||||
reshape : reshape an array.
|
||||
lib.stride_tricks.sliding_window_view :
|
||||
userfriendly and safe function for a creation of sliding window views.
|
||||
|
||||
Notes
|
||||
-----
|
||||
``as_strided`` creates a view into the array given the exact strides
|
||||
and shape. This means it manipulates the internal data structure of
|
||||
ndarray and, if done incorrectly, the array elements can point to
|
||||
invalid memory and can corrupt results or crash your program.
|
||||
It is advisable to always use the original ``x.strides`` when
|
||||
calculating new strides to avoid reliance on a contiguous memory
|
||||
layout.
|
||||
|
||||
Furthermore, arrays created with this function often contain self
|
||||
overlapping memory, so that two elements are identical.
|
||||
Vectorized write operations on such arrays will typically be
|
||||
unpredictable. They may even give different results for small, large,
|
||||
or transposed arrays.
|
||||
|
||||
Since writing to these arrays has to be tested and done with great
|
||||
care, you may want to use ``writeable=False`` to avoid accidental write
|
||||
operations.
|
||||
|
||||
For these reasons it is advisable to avoid ``as_strided`` when
|
||||
possible.
|
||||
"""
|
||||
# first convert input to array, possibly keeping subclass
|
||||
x = np.array(x, copy=None, subok=subok)
|
||||
interface = dict(x.__array_interface__)
|
||||
if shape is not None:
|
||||
interface['shape'] = tuple(shape)
|
||||
if strides is not None:
|
||||
interface['strides'] = tuple(strides)
|
||||
|
||||
array = np.asarray(DummyArray(interface, base=x))
|
||||
# The route via `__interface__` does not preserve structured
|
||||
# dtypes. Since dtype should remain unchanged, we set it explicitly.
|
||||
array.dtype = x.dtype
|
||||
|
||||
view = _maybe_view_as_subclass(x, array)
|
||||
|
||||
if view.flags.writeable and not writeable:
|
||||
view.flags.writeable = False
|
||||
|
||||
return view
|
||||
|
||||
|
||||
def _sliding_window_view_dispatcher(x, window_shape, axis=None, *,
|
||||
subok=None, writeable=None):
|
||||
return (x,)
|
||||
|
||||
|
||||
@array_function_dispatch(
|
||||
_sliding_window_view_dispatcher, module="numpy.lib.stride_tricks"
|
||||
)
|
||||
def sliding_window_view(x, window_shape, axis=None, *,
|
||||
subok=False, writeable=False):
|
||||
"""
|
||||
Create a sliding window view into the array with the given window shape.
|
||||
|
||||
Also known as rolling or moving window, the window slides across all
|
||||
dimensions of the array and extracts subsets of the array at all window
|
||||
positions.
|
||||
|
||||
.. versionadded:: 1.20.0
|
||||
|
||||
Parameters
|
||||
----------
|
||||
x : array_like
|
||||
Array to create the sliding window view from.
|
||||
window_shape : int or tuple of int
|
||||
Size of window over each axis that takes part in the sliding window.
|
||||
If `axis` is not present, must have same length as the number of input
|
||||
array dimensions. Single integers `i` are treated as if they were the
|
||||
tuple `(i,)`.
|
||||
axis : int or tuple of int, optional
|
||||
Axis or axes along which the sliding window is applied.
|
||||
By default, the sliding window is applied to all axes and
|
||||
`window_shape[i]` will refer to axis `i` of `x`.
|
||||
If `axis` is given as a `tuple of int`, `window_shape[i]` will refer to
|
||||
the axis `axis[i]` of `x`.
|
||||
Single integers `i` are treated as if they were the tuple `(i,)`.
|
||||
subok : bool, optional
|
||||
If True, sub-classes will be passed-through, otherwise the returned
|
||||
array will be forced to be a base-class array (default).
|
||||
writeable : bool, optional
|
||||
When true, allow writing to the returned view. The default is false,
|
||||
as this should be used with caution: the returned view contains the
|
||||
same memory location multiple times, so writing to one location will
|
||||
cause others to change.
|
||||
|
||||
Returns
|
||||
-------
|
||||
view : ndarray
|
||||
Sliding window view of the array. The sliding window dimensions are
|
||||
inserted at the end, and the original dimensions are trimmed as
|
||||
required by the size of the sliding window.
|
||||
That is, ``view.shape = x_shape_trimmed + window_shape``, where
|
||||
``x_shape_trimmed`` is ``x.shape`` with every entry reduced by one less
|
||||
than the corresponding window size.
|
||||
|
||||
See Also
|
||||
--------
|
||||
lib.stride_tricks.as_strided: A lower-level and less safe routine for
|
||||
creating arbitrary views from custom shape and strides.
|
||||
broadcast_to: broadcast an array to a given shape.
|
||||
|
||||
Notes
|
||||
-----
|
||||
For many applications using a sliding window view can be convenient, but
|
||||
potentially very slow. Often specialized solutions exist, for example:
|
||||
|
||||
- `scipy.signal.fftconvolve`
|
||||
|
||||
- filtering functions in `scipy.ndimage`
|
||||
|
||||
- moving window functions provided by
|
||||
`bottleneck <https://github.com/pydata/bottleneck>`_.
|
||||
|
||||
As a rough estimate, a sliding window approach with an input size of `N`
|
||||
and a window size of `W` will scale as `O(N*W)` where frequently a special
|
||||
algorithm can achieve `O(N)`. That means that the sliding window variant
|
||||
for a window size of 100 can be a 100 times slower than a more specialized
|
||||
version.
|
||||
|
||||
Nevertheless, for small window sizes, when no custom algorithm exists, or
|
||||
as a prototyping and developing tool, this function can be a good solution.
|
||||
|
||||
Examples
|
||||
--------
|
||||
>>> import numpy as np
|
||||
>>> from numpy.lib.stride_tricks import sliding_window_view
|
||||
>>> x = np.arange(6)
|
||||
>>> x.shape
|
||||
(6,)
|
||||
>>> v = sliding_window_view(x, 3)
|
||||
>>> v.shape
|
||||
(4, 3)
|
||||
>>> v
|
||||
array([[0, 1, 2],
|
||||
[1, 2, 3],
|
||||
[2, 3, 4],
|
||||
[3, 4, 5]])
|
||||
|
||||
This also works in more dimensions, e.g.
|
||||
|
||||
>>> i, j = np.ogrid[:3, :4]
|
||||
>>> x = 10*i + j
|
||||
>>> x.shape
|
||||
(3, 4)
|
||||
>>> x
|
||||
array([[ 0, 1, 2, 3],
|
||||
[10, 11, 12, 13],
|
||||
[20, 21, 22, 23]])
|
||||
>>> shape = (2,2)
|
||||
>>> v = sliding_window_view(x, shape)
|
||||
>>> v.shape
|
||||
(2, 3, 2, 2)
|
||||
>>> v
|
||||
array([[[[ 0, 1],
|
||||
[10, 11]],
|
||||
[[ 1, 2],
|
||||
[11, 12]],
|
||||
[[ 2, 3],
|
||||
[12, 13]]],
|
||||
[[[10, 11],
|
||||
[20, 21]],
|
||||
[[11, 12],
|
||||
[21, 22]],
|
||||
[[12, 13],
|
||||
[22, 23]]]])
|
||||
|
||||
The axis can be specified explicitly:
|
||||
|
||||
>>> v = sliding_window_view(x, 3, 0)
|
||||
>>> v.shape
|
||||
(1, 4, 3)
|
||||
>>> v
|
||||
array([[[ 0, 10, 20],
|
||||
[ 1, 11, 21],
|
||||
[ 2, 12, 22],
|
||||
[ 3, 13, 23]]])
|
||||
|
||||
The same axis can be used several times. In that case, every use reduces
|
||||
the corresponding original dimension:
|
||||
|
||||
>>> v = sliding_window_view(x, (2, 3), (1, 1))
|
||||
>>> v.shape
|
||||
(3, 1, 2, 3)
|
||||
>>> v
|
||||
array([[[[ 0, 1, 2],
|
||||
[ 1, 2, 3]]],
|
||||
[[[10, 11, 12],
|
||||
[11, 12, 13]]],
|
||||
[[[20, 21, 22],
|
||||
[21, 22, 23]]]])
|
||||
|
||||
Combining with stepped slicing (`::step`), this can be used to take sliding
|
||||
views which skip elements:
|
||||
|
||||
>>> x = np.arange(7)
|
||||
>>> sliding_window_view(x, 5)[:, ::2]
|
||||
array([[0, 2, 4],
|
||||
[1, 3, 5],
|
||||
[2, 4, 6]])
|
||||
|
||||
or views which move by multiple elements
|
||||
|
||||
>>> x = np.arange(7)
|
||||
>>> sliding_window_view(x, 3)[::2, :]
|
||||
array([[0, 1, 2],
|
||||
[2, 3, 4],
|
||||
[4, 5, 6]])
|
||||
|
||||
A common application of `sliding_window_view` is the calculation of running
|
||||
statistics. The simplest example is the
|
||||
`moving average <https://en.wikipedia.org/wiki/Moving_average>`_:
|
||||
|
||||
>>> x = np.arange(6)
|
||||
>>> x.shape
|
||||
(6,)
|
||||
>>> v = sliding_window_view(x, 3)
|
||||
>>> v.shape
|
||||
(4, 3)
|
||||
>>> v
|
||||
array([[0, 1, 2],
|
||||
[1, 2, 3],
|
||||
[2, 3, 4],
|
||||
[3, 4, 5]])
|
||||
>>> moving_average = v.mean(axis=-1)
|
||||
>>> moving_average
|
||||
array([1., 2., 3., 4.])
|
||||
|
||||
Note that a sliding window approach is often **not** optimal (see Notes).
|
||||
"""
|
||||
window_shape = (tuple(window_shape)
|
||||
if np.iterable(window_shape)
|
||||
else (window_shape,))
|
||||
# first convert input to array, possibly keeping subclass
|
||||
x = np.array(x, copy=None, subok=subok)
|
||||
|
||||
window_shape_array = np.array(window_shape)
|
||||
if np.any(window_shape_array < 0):
|
||||
raise ValueError('`window_shape` cannot contain negative values')
|
||||
|
||||
if axis is None:
|
||||
axis = tuple(range(x.ndim))
|
||||
if len(window_shape) != len(axis):
|
||||
raise ValueError(f'Since axis is `None`, must provide '
|
||||
f'window_shape for all dimensions of `x`; '
|
||||
f'got {len(window_shape)} window_shape elements '
|
||||
f'and `x.ndim` is {x.ndim}.')
|
||||
else:
|
||||
axis = normalize_axis_tuple(axis, x.ndim, allow_duplicate=True)
|
||||
if len(window_shape) != len(axis):
|
||||
raise ValueError(f'Must provide matching length window_shape and '
|
||||
f'axis; got {len(window_shape)} window_shape '
|
||||
f'elements and {len(axis)} axes elements.')
|
||||
|
||||
out_strides = x.strides + tuple(x.strides[ax] for ax in axis)
|
||||
|
||||
# note: same axis can be windowed repeatedly
|
||||
x_shape_trimmed = list(x.shape)
|
||||
for ax, dim in zip(axis, window_shape):
|
||||
if x_shape_trimmed[ax] < dim:
|
||||
raise ValueError(
|
||||
'window shape cannot be larger than input array shape')
|
||||
x_shape_trimmed[ax] -= dim - 1
|
||||
out_shape = tuple(x_shape_trimmed) + window_shape
|
||||
return as_strided(x, strides=out_strides, shape=out_shape,
|
||||
subok=subok, writeable=writeable)
|
||||
|
||||
|
||||
def _broadcast_to(array, shape, subok, readonly):
|
||||
shape = tuple(shape) if np.iterable(shape) else (shape,)
|
||||
array = np.array(array, copy=None, subok=subok)
|
||||
if not shape and array.shape:
|
||||
raise ValueError('cannot broadcast a non-scalar to a scalar array')
|
||||
if any(size < 0 for size in shape):
|
||||
raise ValueError('all elements of broadcast shape must be non-'
|
||||
'negative')
|
||||
extras = []
|
||||
it = np.nditer(
|
||||
(array,), flags=['multi_index', 'refs_ok', 'zerosize_ok'] + extras,
|
||||
op_flags=['readonly'], itershape=shape, order='C')
|
||||
with it:
|
||||
# never really has writebackifcopy semantics
|
||||
broadcast = it.itviews[0]
|
||||
result = _maybe_view_as_subclass(array, broadcast)
|
||||
# In a future version this will go away
|
||||
if not readonly and array.flags._writeable_no_warn:
|
||||
result.flags.writeable = True
|
||||
result.flags._warn_on_write = True
|
||||
return result
|
||||
|
||||
|
||||
def _broadcast_to_dispatcher(array, shape, subok=None):
|
||||
return (array,)
|
||||
|
||||
|
||||
@array_function_dispatch(_broadcast_to_dispatcher, module='numpy')
|
||||
def broadcast_to(array, shape, subok=False):
|
||||
"""Broadcast an array to a new shape.
|
||||
|
||||
Parameters
|
||||
----------
|
||||
array : array_like
|
||||
The array to broadcast.
|
||||
shape : tuple or int
|
||||
The shape of the desired array. A single integer ``i`` is interpreted
|
||||
as ``(i,)``.
|
||||
subok : bool, optional
|
||||
If True, then sub-classes will be passed-through, otherwise
|
||||
the returned array will be forced to be a base-class array (default).
|
||||
|
||||
Returns
|
||||
-------
|
||||
broadcast : array
|
||||
A readonly view on the original array with the given shape. It is
|
||||
typically not contiguous. Furthermore, more than one element of a
|
||||
broadcasted array may refer to a single memory location.
|
||||
|
||||
Raises
|
||||
------
|
||||
ValueError
|
||||
If the array is not compatible with the new shape according to NumPy's
|
||||
broadcasting rules.
|
||||
|
||||
See Also
|
||||
--------
|
||||
broadcast
|
||||
broadcast_arrays
|
||||
broadcast_shapes
|
||||
|
||||
Notes
|
||||
-----
|
||||
.. versionadded:: 1.10.0
|
||||
|
||||
Examples
|
||||
--------
|
||||
>>> import numpy as np
|
||||
>>> x = np.array([1, 2, 3])
|
||||
>>> np.broadcast_to(x, (3, 3))
|
||||
array([[1, 2, 3],
|
||||
[1, 2, 3],
|
||||
[1, 2, 3]])
|
||||
"""
|
||||
return _broadcast_to(array, shape, subok=subok, readonly=True)
|
||||
|
||||
|
||||
def _broadcast_shape(*args):
|
||||
"""Returns the shape of the arrays that would result from broadcasting the
|
||||
supplied arrays against each other.
|
||||
"""
|
||||
# use the old-iterator because np.nditer does not handle size 0 arrays
|
||||
# consistently
|
||||
b = np.broadcast(*args[:32])
|
||||
# unfortunately, it cannot handle 32 or more arguments directly
|
||||
for pos in range(32, len(args), 31):
|
||||
# ironically, np.broadcast does not properly handle np.broadcast
|
||||
# objects (it treats them as scalars)
|
||||
# use broadcasting to avoid allocating the full array
|
||||
b = broadcast_to(0, b.shape)
|
||||
b = np.broadcast(b, *args[pos:(pos + 31)])
|
||||
return b.shape
|
||||
|
||||
|
||||
_size0_dtype = np.dtype([])
|
||||
|
||||
|
||||
@set_module('numpy')
|
||||
def broadcast_shapes(*args):
|
||||
"""
|
||||
Broadcast the input shapes into a single shape.
|
||||
|
||||
:ref:`Learn more about broadcasting here <basics.broadcasting>`.
|
||||
|
||||
.. versionadded:: 1.20.0
|
||||
|
||||
Parameters
|
||||
----------
|
||||
*args : tuples of ints, or ints
|
||||
The shapes to be broadcast against each other.
|
||||
|
||||
Returns
|
||||
-------
|
||||
tuple
|
||||
Broadcasted shape.
|
||||
|
||||
Raises
|
||||
------
|
||||
ValueError
|
||||
If the shapes are not compatible and cannot be broadcast according
|
||||
to NumPy's broadcasting rules.
|
||||
|
||||
See Also
|
||||
--------
|
||||
broadcast
|
||||
broadcast_arrays
|
||||
broadcast_to
|
||||
|
||||
Examples
|
||||
--------
|
||||
>>> import numpy as np
|
||||
>>> np.broadcast_shapes((1, 2), (3, 1), (3, 2))
|
||||
(3, 2)
|
||||
|
||||
>>> np.broadcast_shapes((6, 7), (5, 6, 1), (7,), (5, 1, 7))
|
||||
(5, 6, 7)
|
||||
"""
|
||||
arrays = [np.empty(x, dtype=_size0_dtype) for x in args]
|
||||
return _broadcast_shape(*arrays)
|
||||
|
||||
|
||||
def _broadcast_arrays_dispatcher(*args, subok=None):
|
||||
return args
|
||||
|
||||
|
||||
@array_function_dispatch(_broadcast_arrays_dispatcher, module='numpy')
|
||||
def broadcast_arrays(*args, subok=False):
|
||||
"""
|
||||
Broadcast any number of arrays against each other.
|
||||
|
||||
Parameters
|
||||
----------
|
||||
*args : array_likes
|
||||
The arrays to broadcast.
|
||||
|
||||
subok : bool, optional
|
||||
If True, then sub-classes will be passed-through, otherwise
|
||||
the returned arrays will be forced to be a base-class array (default).
|
||||
|
||||
Returns
|
||||
-------
|
||||
broadcasted : tuple of arrays
|
||||
These arrays are views on the original arrays. They are typically
|
||||
not contiguous. Furthermore, more than one element of a
|
||||
broadcasted array may refer to a single memory location. If you need
|
||||
to write to the arrays, make copies first. While you can set the
|
||||
``writable`` flag True, writing to a single output value may end up
|
||||
changing more than one location in the output array.
|
||||
|
||||
.. deprecated:: 1.17
|
||||
The output is currently marked so that if written to, a deprecation
|
||||
warning will be emitted. A future version will set the
|
||||
``writable`` flag False so writing to it will raise an error.
|
||||
|
||||
See Also
|
||||
--------
|
||||
broadcast
|
||||
broadcast_to
|
||||
broadcast_shapes
|
||||
|
||||
Examples
|
||||
--------
|
||||
>>> import numpy as np
|
||||
>>> x = np.array([[1,2,3]])
|
||||
>>> y = np.array([[4],[5]])
|
||||
>>> np.broadcast_arrays(x, y)
|
||||
(array([[1, 2, 3],
|
||||
[1, 2, 3]]),
|
||||
array([[4, 4, 4],
|
||||
[5, 5, 5]]))
|
||||
|
||||
Here is a useful idiom for getting contiguous copies instead of
|
||||
non-contiguous views.
|
||||
|
||||
>>> [np.array(a) for a in np.broadcast_arrays(x, y)]
|
||||
[array([[1, 2, 3],
|
||||
[1, 2, 3]]),
|
||||
array([[4, 4, 4],
|
||||
[5, 5, 5]])]
|
||||
|
||||
"""
|
||||
# nditer is not used here to avoid the limit of 32 arrays.
|
||||
# Otherwise, something like the following one-liner would suffice:
|
||||
# return np.nditer(args, flags=['multi_index', 'zerosize_ok'],
|
||||
# order='C').itviews
|
||||
|
||||
args = [np.array(_m, copy=None, subok=subok) for _m in args]
|
||||
|
||||
shape = _broadcast_shape(*args)
|
||||
|
||||
result = [array if array.shape == shape
|
||||
else _broadcast_to(array, shape, subok=subok, readonly=False)
|
||||
for array in args]
|
||||
return tuple(result)
|
Reference in New Issue
Block a user