projektAI/venv/Lib/site-packages/scipy/_lib/_util.py

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2021-06-06 22:13:05 +02:00
import functools
import operator
import sys
import warnings
import numbers
from collections import namedtuple
import inspect
import math
import numpy as np
try:
from numpy.random import Generator as Generator
except ImportError:
class Generator(): # type: ignore[no-redef]
pass
def _lazywhere(cond, arrays, f, fillvalue=None, f2=None):
"""
np.where(cond, x, fillvalue) always evaluates x even where cond is False.
This one only evaluates f(arr1[cond], arr2[cond], ...).
Examples
--------
>>> a, b = np.array([1, 2, 3, 4]), np.array([5, 6, 7, 8])
>>> def f(a, b):
... return a*b
>>> _lazywhere(a > 2, (a, b), f, np.nan)
array([ nan, nan, 21., 32.])
Notice, it assumes that all `arrays` are of the same shape, or can be
broadcasted together.
"""
if fillvalue is None:
if f2 is None:
raise ValueError("One of (fillvalue, f2) must be given.")
else:
fillvalue = np.nan
else:
if f2 is not None:
raise ValueError("Only one of (fillvalue, f2) can be given.")
arrays = np.broadcast_arrays(*arrays)
temp = tuple(np.extract(cond, arr) for arr in arrays)
tcode = np.mintypecode([a.dtype.char for a in arrays])
out = np.full(np.shape(arrays[0]), fill_value=fillvalue, dtype=tcode)
np.place(out, cond, f(*temp))
if f2 is not None:
temp = tuple(np.extract(~cond, arr) for arr in arrays)
np.place(out, ~cond, f2(*temp))
return out
def _lazyselect(condlist, choicelist, arrays, default=0):
"""
Mimic `np.select(condlist, choicelist)`.
Notice, it assumes that all `arrays` are of the same shape or can be
broadcasted together.
All functions in `choicelist` must accept array arguments in the order
given in `arrays` and must return an array of the same shape as broadcasted
`arrays`.
Examples
--------
>>> x = np.arange(6)
>>> np.select([x <3, x > 3], [x**2, x**3], default=0)
array([ 0, 1, 4, 0, 64, 125])
>>> _lazyselect([x < 3, x > 3], [lambda x: x**2, lambda x: x**3], (x,))
array([ 0., 1., 4., 0., 64., 125.])
>>> a = -np.ones_like(x)
>>> _lazyselect([x < 3, x > 3],
... [lambda x, a: x**2, lambda x, a: a * x**3],
... (x, a), default=np.nan)
array([ 0., 1., 4., nan, -64., -125.])
"""
arrays = np.broadcast_arrays(*arrays)
tcode = np.mintypecode([a.dtype.char for a in arrays])
out = np.full(np.shape(arrays[0]), fill_value=default, dtype=tcode)
for index in range(len(condlist)):
func, cond = choicelist[index], condlist[index]
if np.all(cond is False):
continue
cond, _ = np.broadcast_arrays(cond, arrays[0])
temp = tuple(np.extract(cond, arr) for arr in arrays)
np.place(out, cond, func(*temp))
return out
def _aligned_zeros(shape, dtype=float, order="C", align=None):
"""Allocate a new ndarray with aligned memory.
Primary use case for this currently is working around a f2py issue
in NumPy 1.9.1, where dtype.alignment is such that np.zeros() does
not necessarily create arrays aligned up to it.
"""
dtype = np.dtype(dtype)
if align is None:
align = dtype.alignment
if not hasattr(shape, '__len__'):
shape = (shape,)
size = functools.reduce(operator.mul, shape) * dtype.itemsize
buf = np.empty(size + align + 1, np.uint8)
offset = buf.__array_interface__['data'][0] % align
if offset != 0:
offset = align - offset
# Note: slices producing 0-size arrays do not necessarily change
# data pointer --- so we use and allocate size+1
buf = buf[offset:offset+size+1][:-1]
data = np.ndarray(shape, dtype, buf, order=order)
data.fill(0)
return data
def _prune_array(array):
"""Return an array equivalent to the input array. If the input
array is a view of a much larger array, copy its contents to a
newly allocated array. Otherwise, return the input unchanged.
"""
if array.base is not None and array.size < array.base.size // 2:
return array.copy()
return array
def prod(iterable):
"""
Product of a sequence of numbers.
Faster than np.prod for short lists like array shapes, and does
not overflow if using Python integers.
"""
product = 1
for x in iterable:
product *= x
return product
def float_factorial(n: int) -> float:
"""Compute the factorial and return as a float
Returns infinity when result is too large for a double
"""
return float(math.factorial(n)) if n < 171 else np.inf
class DeprecatedImport(object):
"""
Deprecated import with redirection and warning.
Examples
--------
Suppose you previously had in some module::
from foo import spam
If this has to be deprecated, do::
spam = DeprecatedImport("foo.spam", "baz")
to redirect users to use "baz" module instead.
"""
def __init__(self, old_module_name, new_module_name):
self._old_name = old_module_name
self._new_name = new_module_name
__import__(self._new_name)
self._mod = sys.modules[self._new_name]
def __dir__(self):
return dir(self._mod)
def __getattr__(self, name):
warnings.warn("Module %s is deprecated, use %s instead"
% (self._old_name, self._new_name),
DeprecationWarning)
return getattr(self._mod, name)
# copy-pasted from scikit-learn utils/validation.py
def check_random_state(seed):
"""Turn seed into a np.random.RandomState instance
If seed is None (or np.random), return the RandomState singleton used
by np.random.
If seed is an int, return a new RandomState instance seeded with seed.
If seed is already a RandomState instance, return it.
If seed is a new-style np.random.Generator, return it.
Otherwise, raise ValueError.
"""
if seed is None or seed is np.random:
return np.random.mtrand._rand
if isinstance(seed, (numbers.Integral, np.integer)):
return np.random.RandomState(seed)
if isinstance(seed, np.random.RandomState):
return seed
try:
# Generator is only available in numpy >= 1.17
if isinstance(seed, np.random.Generator):
return seed
except AttributeError:
pass
raise ValueError('%r cannot be used to seed a numpy.random.RandomState'
' instance' % seed)
def _asarray_validated(a, check_finite=True,
sparse_ok=False, objects_ok=False, mask_ok=False,
as_inexact=False):
"""
Helper function for SciPy argument validation.
Many SciPy linear algebra functions do support arbitrary array-like
input arguments. Examples of commonly unsupported inputs include
matrices containing inf/nan, sparse matrix representations, and
matrices with complicated elements.
Parameters
----------
a : array_like
The array-like input.
check_finite : bool, optional
Whether to check that the input matrices contain only finite numbers.
Disabling may give a performance gain, but may result in problems
(crashes, non-termination) if the inputs do contain infinities or NaNs.
Default: True
sparse_ok : bool, optional
True if scipy sparse matrices are allowed.
objects_ok : bool, optional
True if arrays with dype('O') are allowed.
mask_ok : bool, optional
True if masked arrays are allowed.
as_inexact : bool, optional
True to convert the input array to a np.inexact dtype.
Returns
-------
ret : ndarray
The converted validated array.
"""
if not sparse_ok:
import scipy.sparse
if scipy.sparse.issparse(a):
msg = ('Sparse matrices are not supported by this function. '
'Perhaps one of the scipy.sparse.linalg functions '
'would work instead.')
raise ValueError(msg)
if not mask_ok:
if np.ma.isMaskedArray(a):
raise ValueError('masked arrays are not supported')
toarray = np.asarray_chkfinite if check_finite else np.asarray
a = toarray(a)
if not objects_ok:
if a.dtype is np.dtype('O'):
raise ValueError('object arrays are not supported')
if as_inexact:
if not np.issubdtype(a.dtype, np.inexact):
a = toarray(a, dtype=np.float_)
return a
# Add a replacement for inspect.getfullargspec()/
# The version below is borrowed from Django,
# https://github.com/django/django/pull/4846.
# Note an inconsistency between inspect.getfullargspec(func) and
# inspect.signature(func). If `func` is a bound method, the latter does *not*
# list `self` as a first argument, while the former *does*.
# Hence, cook up a common ground replacement: `getfullargspec_no_self` which
# mimics `inspect.getfullargspec` but does not list `self`.
#
# This way, the caller code does not need to know whether it uses a legacy
# .getfullargspec or a bright and shiny .signature.
FullArgSpec = namedtuple('FullArgSpec',
['args', 'varargs', 'varkw', 'defaults',
'kwonlyargs', 'kwonlydefaults', 'annotations'])
def getfullargspec_no_self(func):
"""inspect.getfullargspec replacement using inspect.signature.
If func is a bound method, do not list the 'self' parameter.
Parameters
----------
func : callable
A callable to inspect
Returns
-------
fullargspec : FullArgSpec(args, varargs, varkw, defaults, kwonlyargs,
kwonlydefaults, annotations)
NOTE: if the first argument of `func` is self, it is *not*, I repeat
*not*, included in fullargspec.args.
This is done for consistency between inspect.getargspec() under
Python 2.x, and inspect.signature() under Python 3.x.
"""
sig = inspect.signature(func)
args = [
p.name for p in sig.parameters.values()
if p.kind in [inspect.Parameter.POSITIONAL_OR_KEYWORD,
inspect.Parameter.POSITIONAL_ONLY]
]
varargs = [
p.name for p in sig.parameters.values()
if p.kind == inspect.Parameter.VAR_POSITIONAL
]
varargs = varargs[0] if varargs else None
varkw = [
p.name for p in sig.parameters.values()
if p.kind == inspect.Parameter.VAR_KEYWORD
]
varkw = varkw[0] if varkw else None
defaults = tuple(
p.default for p in sig.parameters.values()
if (p.kind == inspect.Parameter.POSITIONAL_OR_KEYWORD and
p.default is not p.empty)
) or None
kwonlyargs = [
p.name for p in sig.parameters.values()
if p.kind == inspect.Parameter.KEYWORD_ONLY
]
kwdefaults = {p.name: p.default for p in sig.parameters.values()
if p.kind == inspect.Parameter.KEYWORD_ONLY and
p.default is not p.empty}
annotations = {p.name: p.annotation for p in sig.parameters.values()
if p.annotation is not p.empty}
return FullArgSpec(args, varargs, varkw, defaults, kwonlyargs,
kwdefaults or None, annotations)
class MapWrapper(object):
"""
Parallelisation wrapper for working with map-like callables, such as
`multiprocessing.Pool.map`.
Parameters
----------
pool : int or map-like callable
If `pool` is an integer, then it specifies the number of threads to
use for parallelization. If ``int(pool) == 1``, then no parallel
processing is used and the map builtin is used.
If ``pool == -1``, then the pool will utilize all available CPUs.
If `pool` is a map-like callable that follows the same
calling sequence as the built-in map function, then this callable is
used for parallelization.
"""
def __init__(self, pool=1):
self.pool = None
self._mapfunc = map
self._own_pool = False
if callable(pool):
self.pool = pool
self._mapfunc = self.pool
else:
from multiprocessing import Pool
# user supplies a number
if int(pool) == -1:
# use as many processors as possible
self.pool = Pool()
self._mapfunc = self.pool.map
self._own_pool = True
elif int(pool) == 1:
pass
elif int(pool) > 1:
# use the number of processors requested
self.pool = Pool(processes=int(pool))
self._mapfunc = self.pool.map
self._own_pool = True
else:
raise RuntimeError("Number of workers specified must be -1,"
" an int >= 1, or an object with a 'map' method")
def __enter__(self):
return self
def terminate(self):
if self._own_pool:
self.pool.terminate()
def join(self):
if self._own_pool:
self.pool.join()
def close(self):
if self._own_pool:
self.pool.close()
def __exit__(self, exc_type, exc_value, traceback):
if self._own_pool:
self.pool.close()
self.pool.terminate()
def __call__(self, func, iterable):
# only accept one iterable because that's all Pool.map accepts
try:
return self._mapfunc(func, iterable)
except TypeError as e:
# wrong number of arguments
raise TypeError("The map-like callable must be of the"
" form f(func, iterable)") from e
def rng_integers(gen, low, high=None, size=None, dtype='int64',
endpoint=False):
"""
Return random integers from low (inclusive) to high (exclusive), or if
endpoint=True, low (inclusive) to high (inclusive). Replaces
`RandomState.randint` (with endpoint=False) and
`RandomState.random_integers` (with endpoint=True).
Return random integers from the "discrete uniform" distribution of the
specified dtype. If high is None (the default), then results are from
0 to low.
Parameters
----------
gen: {None, np.random.RandomState, np.random.Generator}
Random number generator. If None, then the np.random.RandomState
singleton is used.
low: int or array-like of ints
Lowest (signed) integers to be drawn from the distribution (unless
high=None, in which case this parameter is 0 and this value is used
for high).
high: int or array-like of ints
If provided, one above the largest (signed) integer to be drawn from
the distribution (see above for behavior if high=None). If array-like,
must contain integer values.
size: None
Output shape. If the given shape is, e.g., (m, n, k), then m * n * k
samples are drawn. Default is None, in which case a single value is
returned.
dtype: {str, dtype}, optional
Desired dtype of the result. All dtypes are determined by their name,
i.e., 'int64', 'int', etc, so byteorder is not available and a specific
precision may have different C types depending on the platform.
The default value is np.int_.
endpoint: bool, optional
If True, sample from the interval [low, high] instead of the default
[low, high) Defaults to False.
Returns
-------
out: int or ndarray of ints
size-shaped array of random integers from the appropriate distribution,
or a single such random int if size not provided.
"""
if isinstance(gen, Generator):
return gen.integers(low, high=high, size=size, dtype=dtype,
endpoint=endpoint)
else:
if gen is None:
# default is RandomState singleton used by np.random.
gen = np.random.mtrand._rand
if endpoint:
# inclusive of endpoint
# remember that low and high can be arrays, so don't modify in
# place
if high is None:
return gen.randint(low + 1, size=size, dtype=dtype)
if high is not None:
return gen.randint(low, high=high + 1, size=size, dtype=dtype)
# exclusive
return gen.randint(low, high=high, size=size, dtype=dtype)