#
# * The source code in this file is developed independently by NEC Corporation.
#
# # NLCPy License #
#
# Copyright (c) 2020 NEC Corporation
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
# * Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
# * Neither NEC Corporation nor the names of its contributors may be
# used to endorse or promote products derived from this software
# without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
import threading
import contextlib
_ERR_IGNORE = 0
_ERR_WARN = 1
_ERR_RAISE = 2
_ERR_CALL = 3
_ERR_PRINT = 4
_ERR_LOG = 5
_ERR_DEFAULT = 521
_SHIFT_DIVIDEBYZERO = 0
_SHIFT_OVERFLOW = 3
_SHIFT_UNDERFLOW = 6
_SHIFT_INVALID = 9
_errdict = {"ignore": _ERR_IGNORE,
"warn": _ERR_WARN,
"raise": _ERR_RAISE,
"print": _ERR_PRINT}
_errdict_rev = {value: key for key, value in _errdict.items()}
_thread_local = threading.local()
class _ErrState:
def __init__(self):
self._errstate = _ERR_DEFAULT
@staticmethod
def get():
try:
errstate = _thread_local._errstate
except AttributeError:
errstate = _ErrState()
_thread_local._errstate = errstate
return errstate
def set(self, state):
self._errstate = state
# ----------------------------------------------------------------------------
# Set how floating-point errors are handled.
# see: https://docs.scipy.org/doc/numpy/reference/generated/
# numpy.seterr.html#numpy.seterr
# ----------------------------------------------------------------------------
[docs]def seterr(all=None, divide=None, over=None, under=None, invalid=None):
"""Sets how floating-point errors are handled.
Parameters
----------
all : {'ignore', 'warn', 'raise', 'print'}, optional
Sets treatment for all types of floating-point errors at once:
- ignore: Take no action when the exception occurs.
- warn: Print a *RuntimeWarning*.
- raise: Raise a *FloatingPointError*.
- print: Print a warning directly to stdout.
The default is not to change the current behavior.
divide : {'ignore', 'warn', 'raise', 'print'}, optional
Treatment for division by zero.
over : {'ignore', 'warn', 'raise', 'print'}, optional
Treatment for floating-point overflow.
under : {'ignore', 'warn', 'raise', 'print'}, optional
Treatment for floating-point underflow.
invalid : {'ignore', 'warn', 'raise', 'print'}, optional
Treatment for invalid floating-point operation.
Returns
-------
old_settings : dict
Dictionary containing the old settings.
Restriction
-----------
- If the 'call' mode or the 'log' mode is specified for each parameter,
*KeyError* occurs.
Note
----
- The floating-point exceptions are defined in the IEEE 754 standard:
- Division by zero: infinite result obtained from finite numbers.
- Overflow: result too large to be expressed.
- Underflow: result so close to zero that some precision was lost.
- Invalid operation: result is not an expressible number, typically
indicates that a NaN was produced.
See Also
--------
geterr : Gets the current way of handling floating-point errors.
errstate : Context manager for floating-point error handling.
Examples
--------
>>> import nlcpy as vp
>>> old_settings = vp.seterr(all='ignore') #seterr to known value
>>> vp.seterr(over='raise')
{'divide': 'ignore', 'over': 'ignore', 'under': 'ignore', 'invalid': 'ignore'}
>>> vp.seterr(**old_settings) # reset to default
{'divide': 'ignore', 'over': 'raise', 'under': 'ignore', 'invalid': 'ignore'}
"""
old = geterr()
if divide is None:
divide = all or old['divide']
if over is None:
over = all or old['over']
if under is None:
under = all or old['under']
if invalid is None:
invalid = all or old['invalid']
maskvalue = ((_errdict[divide] << _SHIFT_DIVIDEBYZERO) +
(_errdict[over] << _SHIFT_OVERFLOW) +
(_errdict[under] << _SHIFT_UNDERFLOW) +
(_errdict[invalid] << _SHIFT_INVALID))
_ErrState.get().set(maskvalue)
return old
# ----------------------------------------------------------------------------
# Get the current way of handling floating-point errors.
# see: https://docs.scipy.org/doc/numpy/reference/generated/
# numpy.geterr.html#numpy.geterr
# ----------------------------------------------------------------------------
[docs]def geterr():
"""Gets the current way of handling floating-point errors.
Returns
-------
res : dict
A dictionary with keys "divide", "over", "under", and "invalid",
whose values are from the strings "ignore", "print", "warn", and "raise".
The keys represent possible floating-point exceptions, and the values
define how these exceptions are handled.
The elements of the shape tuple give the lengths of the corresponding array
dimensions.
Note
----
- For complete documentation of the types of floating-point exceptions and treatment
options, see :func:`nlcpy.seterr`.
See Also
--------
seterr : Sets how floating-point errors are handled.
errstate : Context manager for floating-point error handling.
Examples
--------
>>> import nlcpy as vp
>>> from collections import OrderedDict
>>> sorted(vp.geterr().items())
[('divide', 'warn'), ('invalid', 'warn'), ('over', 'warn'), ('under', 'ignore')]
>>> vp.arange(3.) / vp.arange(3.)
array([nan, 1., 1.])
"""
maskvalue = _ErrState.get()._errstate
mask = 7
res = {}
val = (maskvalue >> _SHIFT_DIVIDEBYZERO) & mask
res['divide'] = _errdict_rev[val]
val = (maskvalue >> _SHIFT_OVERFLOW) & mask
res['over'] = _errdict_rev[val]
val = (maskvalue >> _SHIFT_UNDERFLOW) & mask
res['under'] = _errdict_rev[val]
val = (maskvalue >> _SHIFT_INVALID) & mask
res['invalid'] = _errdict_rev[val]
return res
[docs]class errstate(contextlib.ContextDecorator):
"""Context manager for floating-point error handling.
Using an instance of `errstate` as a context manager allows statements in
that context to execute with a known error handling behavior. Upon entering
the context the error handling is set with `seterr`, and upon exiting it is
reset to what it was before.
Parameters
----------
kwargs : {divide, over, under, invalid}
Keyword arguments. The valid keywords are the possible floating-point
exceptions. Each keyword should have a string value that defines the
treatment for the particular error. Possible values are
{'ignore', 'warn', 'raise', 'print'}.
See Also
--------
seterr : Sets how floating-point errors are handled.
geterr : Gets the current way of handling floating-point errors.
Examples
--------
>>> import nlcpy as vp
>>> olderr = vp.seterr(all='ignore') # Set error handling to known state.
>>> vp.arange(3) / 0.
array([nan, inf, inf])
>>> with vp.errstate(divide='warn'):
... vp.arange(3) / 0. # doctest: +SKIP
<stdin>:2: RuntimeWarning: divide by zero encountered \
in any of (nlcpy_arange, nlcpy_true_divide)
array([nan, inf, inf])
>>> vp.sqrt(-1)
array(nan)
>>> with vp.errstate(invalid='raise'): # doctest: +SKIP
... vp.sqrt(-1)
Traceback (most recent call last):
...
FloatingPointError: invalid value encountered in (nlcpy_sqrt)
Outside the context the error handling behavior has not changed:
>>> vp.geterr()
{'divide': 'ignore', 'over': 'ignore', 'under': 'ignore', 'invalid': 'ignore'}
>>> _ = vp.seterr(**olderr)
"""
def __init__(self, *args, **kwargs):
self.kwargs = kwargs
[docs] def __enter__(self):
self.oldstate = seterr(**self.kwargs)
[docs] def __exit__(self, *exc_info):
seterr(**self.oldstate)