/usr/lib/python3/dist-packages/xarray/core/duck_array_ops.py is in python3-xarray 0.10.2-1.
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Currently, this means Dask or NumPy arrays. None of these functions should
accept or return xarray objects.
"""
from __future__ import absolute_import, division, print_function
import contextlib
import inspect
import warnings
from functools import partial
import numpy as np
import pandas as pd
from . import dask_array_ops, dtypes, npcompat, nputils
from .nputils import nanfirst, nanlast
from .pycompat import dask_array_type
try:
import bottleneck as bn
has_bottleneck = True
except ImportError:
# use numpy methods instead
bn = np
has_bottleneck = False
try:
import dask.array as da
has_dask = True
except ImportError:
has_dask = False
def _dask_or_eager_func(name, eager_module=np, list_of_args=False,
n_array_args=1):
"""Create a function that dispatches to dask for dask array inputs."""
if has_dask:
def f(*args, **kwargs):
if list_of_args:
dispatch_args = args[0]
else:
dispatch_args = args[:n_array_args]
if any(isinstance(a, da.Array) for a in dispatch_args):
module = da
else:
module = eager_module
return getattr(module, name)(*args, **kwargs)
else:
def f(data, *args, **kwargs):
return getattr(eager_module, name)(data, *args, **kwargs)
return f
def fail_on_dask_array_input(values, msg=None, func_name=None):
if isinstance(values, dask_array_type):
if msg is None:
msg = '%r is not yet a valid method on dask arrays'
if func_name is None:
func_name = inspect.stack()[1][3]
raise NotImplementedError(msg % func_name)
around = _dask_or_eager_func('around')
isclose = _dask_or_eager_func('isclose')
notnull = _dask_or_eager_func('notnull', pd)
_isnull = _dask_or_eager_func('isnull', pd)
def isnull(data):
# GH837, GH861
# isnull fcn from pandas will throw TypeError when run on numpy structured
# array therefore for dims that are np structured arrays we assume all
# data is present
try:
return _isnull(data)
except TypeError:
return np.zeros(data.shape, dtype=bool)
transpose = _dask_or_eager_func('transpose')
_where = _dask_or_eager_func('where', n_array_args=3)
insert = _dask_or_eager_func('insert')
take = _dask_or_eager_func('take')
broadcast_to = _dask_or_eager_func('broadcast_to')
_concatenate = _dask_or_eager_func('concatenate', list_of_args=True)
_stack = _dask_or_eager_func('stack', list_of_args=True)
array_all = _dask_or_eager_func('all')
array_any = _dask_or_eager_func('any')
tensordot = _dask_or_eager_func('tensordot', n_array_args=2)
def asarray(data):
return data if isinstance(data, dask_array_type) else np.asarray(data)
def as_shared_dtype(scalars_or_arrays):
"""Cast a arrays to a shared dtype using xarray's type promotion rules."""
arrays = [asarray(x) for x in scalars_or_arrays]
# Pass arrays directly instead of dtypes to result_type so scalars
# get handled properly.
# Note that result_type() safely gets the dtype from dask arrays without
# evaluating them.
out_type = dtypes.result_type(*arrays)
return [x.astype(out_type, copy=False) for x in arrays]
def as_like_arrays(*data):
if all(isinstance(d, dask_array_type) for d in data):
return data
else:
return tuple(np.asarray(d) for d in data)
def allclose_or_equiv(arr1, arr2, rtol=1e-5, atol=1e-8):
"""Like np.allclose, but also allows values to be NaN in both arrays
"""
arr1, arr2 = as_like_arrays(arr1, arr2)
if arr1.shape != arr2.shape:
return False
return bool(
isclose(arr1, arr2, rtol=rtol, atol=atol, equal_nan=True).all())
def array_equiv(arr1, arr2):
"""Like np.array_equal, but also allows values to be NaN in both arrays
"""
arr1, arr2 = as_like_arrays(arr1, arr2)
if arr1.shape != arr2.shape:
return False
flag_array = (arr1 == arr2)
flag_array |= (isnull(arr1) & isnull(arr2))
return bool(flag_array.all())
def array_notnull_equiv(arr1, arr2):
"""Like np.array_equal, but also allows values to be NaN in either or both
arrays
"""
arr1, arr2 = as_like_arrays(arr1, arr2)
if arr1.shape != arr2.shape:
return False
flag_array = (arr1 == arr2)
flag_array |= isnull(arr1)
flag_array |= isnull(arr2)
return bool(flag_array.all())
def count(data, axis=None):
"""Count the number of non-NA in this array along the given axis or axes
"""
return sum(~isnull(data), axis=axis)
def where(condition, x, y):
"""Three argument where() with better dtype promotion rules."""
return _where(condition, *as_shared_dtype([x, y]))
def where_method(data, cond, other=dtypes.NA):
if other is dtypes.NA:
other = dtypes.get_fill_value(data.dtype)
return where(cond, data, other)
def fillna(data, other):
return where(isnull(data), other, data)
def concatenate(arrays, axis=0):
"""concatenate() with better dtype promotion rules."""
return _concatenate(as_shared_dtype(arrays), axis=axis)
def stack(arrays, axis=0):
"""stack() with better dtype promotion rules."""
return _stack(as_shared_dtype(arrays), axis=axis)
@contextlib.contextmanager
def _ignore_warnings_if(condition):
if condition:
with warnings.catch_warnings():
warnings.simplefilter('ignore')
yield
else:
yield
def _nansum_object(value, axis=None, **kwargs):
""" In house nansum for object array """
value = fillna(value, 0)
return _dask_or_eager_func('sum')(value, axis=axis, **kwargs)
def _nan_minmax_object(func, get_fill_value, value, axis=None, **kwargs):
""" In house nanmin and nanmax for object array """
fill_value = get_fill_value(value.dtype)
valid_count = count(value, axis=axis)
filled_value = fillna(value, fill_value)
data = _dask_or_eager_func(func)(filled_value, axis=axis, **kwargs)
if not hasattr(data, 'dtype'): # scalar case
data = dtypes.fill_value(value.dtype) if valid_count == 0 else data
return np.array(data, dtype=value.dtype)
return where_method(data, valid_count != 0)
def _nan_argminmax_object(func, get_fill_value, value, axis=None, **kwargs):
""" In house nanargmin, nanargmax for object arrays. Always return integer
type """
fill_value = get_fill_value(value.dtype)
valid_count = count(value, axis=axis)
value = fillna(value, fill_value)
data = _dask_or_eager_func(func)(value, axis=axis, **kwargs)
# dask seems return non-integer type
if isinstance(value, dask_array_type):
data = data.astype(int)
if (valid_count == 0).any():
raise ValueError('All-NaN slice encountered')
return np.array(data, dtype=int)
def _nanmean_ddof_object(ddof, value, axis=None, **kwargs):
""" In house nanmean. ddof argument will be used in _nanvar method """
valid_count = count(value, axis=axis)
value = fillna(value, 0)
# As dtype inference is impossible for object dtype, we assume float
# https://github.com/dask/dask/issues/3162
dtype = kwargs.pop('dtype', None)
if dtype is None and value.dtype.kind == 'O':
dtype = value.dtype if value.dtype.kind in ['cf'] else float
data = _dask_or_eager_func('sum')(value, axis=axis, dtype=dtype, **kwargs)
data = data / (valid_count - ddof)
return where_method(data, valid_count != 0)
def _nanvar_object(value, axis=None, **kwargs):
ddof = kwargs.pop('ddof', 0)
kwargs_mean = kwargs.copy()
kwargs_mean.pop('keepdims', None)
value_mean = _nanmean_ddof_object(ddof=0, value=value, axis=axis,
keepdims=True, **kwargs_mean)
squared = (value.astype(value_mean.dtype) - value_mean)**2
return _nanmean_ddof_object(ddof, squared, axis=axis, **kwargs)
_nan_object_funcs = {
'sum': _nansum_object,
'min': partial(_nan_minmax_object, 'min', dtypes.get_pos_infinity),
'max': partial(_nan_minmax_object, 'max', dtypes.get_neg_infinity),
'argmin': partial(_nan_argminmax_object, 'argmin',
dtypes.get_pos_infinity),
'argmax': partial(_nan_argminmax_object, 'argmax',
dtypes.get_neg_infinity),
'mean': partial(_nanmean_ddof_object, 0),
'var': _nanvar_object,
}
def _create_nan_agg_method(name, numeric_only=False, np_compat=False,
no_bottleneck=False, coerce_strings=False,
keep_dims=False):
def f(values, axis=None, skipna=None, **kwargs):
if kwargs.pop('out', None) is not None:
raise TypeError('`out` is not valid for {}'.format(name))
# If dtype is supplied, we use numpy's method.
dtype = kwargs.get('dtype', None)
values = asarray(values)
# dask requires dtype argument for object dtype
if (values.dtype == 'object' and name in ['sum', ]):
kwargs['dtype'] = values.dtype if dtype is None else dtype
if coerce_strings and values.dtype.kind in 'SU':
values = values.astype(object)
if skipna or (skipna is None and values.dtype.kind in 'cfO'):
if values.dtype.kind not in ['u', 'i', 'f', 'c']:
func = _nan_object_funcs.get(name, None)
using_numpy_nan_func = True
if func is None or values.dtype.kind not in 'Ob':
raise NotImplementedError(
'skipna=True not yet implemented for %s with dtype %s'
% (name, values.dtype))
else:
nanname = 'nan' + name
if (isinstance(axis, tuple) or not values.dtype.isnative or
no_bottleneck or (dtype is not None and
np.dtype(dtype) != values.dtype)):
# bottleneck can't handle multiple axis arguments or
# non-native endianness
if np_compat:
eager_module = npcompat
else:
eager_module = np
else:
kwargs.pop('dtype', None)
eager_module = bn
func = _dask_or_eager_func(nanname, eager_module)
using_numpy_nan_func = (eager_module is np or
eager_module is npcompat)
else:
func = _dask_or_eager_func(name)
using_numpy_nan_func = False
with _ignore_warnings_if(using_numpy_nan_func):
try:
return func(values, axis=axis, **kwargs)
except AttributeError:
if isinstance(values, dask_array_type):
try: # dask/dask#3133 dask sometimes needs dtype argument
return func(values, axis=axis, dtype=values.dtype,
**kwargs)
except AttributeError:
msg = '%s is not yet implemented on dask arrays' % name
else:
assert using_numpy_nan_func
msg = ('%s is not available with skipna=False with the '
'installed version of numpy; upgrade to numpy 1.12 '
'or newer to use skipna=True or skipna=None' % name)
raise NotImplementedError(msg)
f.numeric_only = numeric_only
f.keep_dims = keep_dims
f.__name__ = name
return f
argmax = _create_nan_agg_method('argmax', coerce_strings=True)
argmin = _create_nan_agg_method('argmin', coerce_strings=True)
max = _create_nan_agg_method('max', coerce_strings=True)
min = _create_nan_agg_method('min', coerce_strings=True)
sum = _create_nan_agg_method('sum', numeric_only=True)
mean = _create_nan_agg_method('mean', numeric_only=True)
std = _create_nan_agg_method('std', numeric_only=True)
var = _create_nan_agg_method('var', numeric_only=True)
median = _create_nan_agg_method('median', numeric_only=True)
prod = _create_nan_agg_method('prod', numeric_only=True, no_bottleneck=True)
cumprod = _create_nan_agg_method('cumprod', numeric_only=True, np_compat=True,
no_bottleneck=True, keep_dims=True)
cumsum = _create_nan_agg_method('cumsum', numeric_only=True, np_compat=True,
no_bottleneck=True, keep_dims=True)
_fail_on_dask_array_input_skipna = partial(
fail_on_dask_array_input,
msg='%r with skipna=True is not yet implemented on dask arrays')
def first(values, axis, skipna=None):
"""Return the first non-NA elements in this array along the given axis
"""
if (skipna or skipna is None) and values.dtype.kind not in 'iSU':
# only bother for dtypes that can hold NaN
_fail_on_dask_array_input_skipna(values)
return nanfirst(values, axis)
return take(values, 0, axis=axis)
def last(values, axis, skipna=None):
"""Return the last non-NA elements in this array along the given axis
"""
if (skipna or skipna is None) and values.dtype.kind not in 'iSU':
# only bother for dtypes that can hold NaN
_fail_on_dask_array_input_skipna(values)
return nanlast(values, axis)
return take(values, -1, axis=axis)
def rolling_window(array, axis, window, center, fill_value):
"""
Make an ndarray with a rolling window of axis-th dimension.
The rolling dimension will be placed at the last dimension.
"""
if isinstance(array, dask_array_type):
return dask_array_ops.rolling_window(
array, axis, window, center, fill_value)
else: # np.ndarray
return nputils.rolling_window(
array, axis, window, center, fill_value)
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