"""
pint.quantity
~~~~~~~~~~~~~
:copyright: 2016 by Pint Authors, see AUTHORS for more details.
:license: BSD, see LICENSE for more details.
"""
import bisect
import contextlib
import copy
import datetime
import functools
import locale
import math
import numbers
import operator
import re
import warnings
from pkg_resources.extern.packaging import version
from .compat import SKIP_ARRAY_FUNCTION_CHANGE_WARNING # noqa: F401
from .compat import (
ARRAY_FALLBACK,
NUMPY_VER,
BehaviorChangeWarning,
_to_magnitude,
array_function_change_msg,
babel_parse,
eq,
is_duck_array_type,
is_upcast_type,
ndarray,
np,
)
from .definitions import UnitDefinition
from .errors import (
DimensionalityError,
OffsetUnitCalculusError,
PintTypeError,
UnitStrippedWarning,
)
from .formatting import (
_pretty_fmt_exponent,
ndarray_to_latex,
ndarray_to_latex_parts,
remove_custom_flags,
siunitx_format_unit,
)
from .numpy_func import (
HANDLED_UFUNCS,
copy_units_output_ufuncs,
get_op_output_unit,
matching_input_copy_units_output_ufuncs,
matching_input_set_units_output_ufuncs,
numpy_wrap,
op_units_output_ufuncs,
set_units_ufuncs,
)
from .util import (
PrettyIPython,
SharedRegistryObject,
UnitsContainer,
infer_base_unit,
logger,
to_units_container,
)
class _Exception(Exception): # pragma: no cover
def __init__(self, internal):
self.internal = internal
def reduce_dimensions(f):
def wrapped(self, *args, **kwargs):
result = f(self, *args, **kwargs)
if result._REGISTRY.auto_reduce_dimensions:
return result.to_reduced_units()
else:
return result
return wrapped
def ireduce_dimensions(f):
def wrapped(self, *args, **kwargs):
result = f(self, *args, **kwargs)
if result._REGISTRY.auto_reduce_dimensions:
result.ito_reduced_units()
return result
return wrapped
def check_implemented(f):
def wrapped(self, *args, **kwargs):
other = args[0]
if is_upcast_type(type(other)):
return NotImplemented
# pandas often gets to arrays of quantities [ Q_(1,"m"), Q_(2,"m")]
# and expects Quantity * array[Quantity] should return NotImplemented
elif isinstance(other, list) and other and isinstance(other[0], type(self)):
return NotImplemented
result = f(self, *args, **kwargs)
return result
return wrapped
[docs]@contextlib.contextmanager
def printoptions(*args, **kwargs):
"""Numpy printoptions context manager released with version 1.15.0
https://docs.scipy.org/doc/numpy/reference/generated/numpy.printoptions.html
"""
opts = np.get_printoptions()
try:
np.set_printoptions(*args, **kwargs)
yield np.get_printoptions()
finally:
np.set_printoptions(**opts)
[docs]class Quantity(PrettyIPython, SharedRegistryObject):
"""Implements a class to describe a physical quantity:
the product of a numerical value and a unit of measurement.
Parameters
----------
value : str, pint.Quantity or any numeric type
Value of the physical quantity to be created.
units : UnitsContainer, str or pint.Quantity
Units of the physical quantity to be created.
Returns
-------
"""
#: Default formatting string.
default_format = ""
@property
def force_ndarray(self):
return self._REGISTRY.force_ndarray
@property
def force_ndarray_like(self):
return self._REGISTRY.force_ndarray_like
def __reduce__(self):
"""Allow pickling quantities. Since UnitRegistries are not pickled, upon
unpickling the new object is always attached to the application registry.
"""
from . import _unpickle
# Note: type(self) would be a mistake as subclasses built by
# build_quantity_class can't be pickled
return _unpickle, (Quantity, self.magnitude, self._units)
def __new__(cls, value, units=None):
global SKIP_ARRAY_FUNCTION_CHANGE_WARNING
if is_upcast_type(type(value)):
raise TypeError(f"Quantity cannot wrap upcast type {type(value)}")
elif units is None:
if isinstance(value, str):
if value == "":
raise ValueError(
"Expression to parse as Quantity cannot " "be an empty string."
)
ureg = SharedRegistryObject.__new__(cls)._REGISTRY
inst = ureg.parse_expression(value)
return cls.__new__(cls, inst)
elif isinstance(value, cls):
inst = copy.copy(value)
else:
inst = SharedRegistryObject.__new__(cls)
inst._magnitude = _to_magnitude(
value, inst.force_ndarray, inst.force_ndarray_like
)
inst._units = UnitsContainer()
elif isinstance(units, (UnitsContainer, UnitDefinition)):
inst = SharedRegistryObject.__new__(cls)
inst._magnitude = _to_magnitude(
value, inst.force_ndarray, inst.force_ndarray_like
)
inst._units = units
elif isinstance(units, str):
inst = SharedRegistryObject.__new__(cls)
inst._magnitude = _to_magnitude(
value, inst.force_ndarray, inst.force_ndarray_like
)
inst._units = inst._REGISTRY.parse_units(units)._units
elif isinstance(units, SharedRegistryObject):
if isinstance(units, Quantity) and units.magnitude != 1:
inst = copy.copy(units)
logger.warning(
"Creating new Quantity using a non unity " "Quantity as units."
)
else:
inst = SharedRegistryObject.__new__(cls)
inst._units = units._units
inst._magnitude = _to_magnitude(
value, inst.force_ndarray, inst.force_ndarray_like
)
else:
raise TypeError(
"units must be of type str, Quantity or "
"UnitsContainer; not {}.".format(type(units))
)
inst.__used = False
inst.__handling = None
if not SKIP_ARRAY_FUNCTION_CHANGE_WARNING and isinstance(
inst._magnitude, ndarray
):
warnings.warn(array_function_change_msg, BehaviorChangeWarning)
SKIP_ARRAY_FUNCTION_CHANGE_WARNING = True
return inst
@property
def debug_used(self):
return self.__used
def __iter__(self):
# Make sure that, if self.magnitude is not iterable, we raise TypeError as soon
# as one calls iter(self) without waiting for the first element to be drawn from
# the iterator
it_magnitude = iter(self.magnitude)
def it_outer():
for element in it_magnitude:
yield self.__class__(element, self._units)
return it_outer()
def __copy__(self):
ret = self.__class__(copy.copy(self._magnitude), self._units)
ret.__used = self.__used
return ret
def __deepcopy__(self, memo):
ret = self.__class__(
copy.deepcopy(self._magnitude, memo), copy.deepcopy(self._units, memo)
)
ret.__used = self.__used
return ret
def __str__(self):
return format(self)
def __bytes__(self):
return str(self).encode(locale.getpreferredencoding())
def __repr__(self):
return f"<Quantity({self._magnitude}, '{self._units}')>"
def __hash__(self):
self_base = self.to_base_units()
if self_base.dimensionless:
return hash(self_base.magnitude)
else:
return hash((self_base.__class__, self_base.magnitude, self_base.units))
_exp_pattern = re.compile(r"([0-9]\.?[0-9]*)e(-?)\+?0*([0-9]+)")
def __format__(self, spec):
spec = spec or self.default_format
if "L" in spec:
allf = plain_allf = r"{}\ {}"
else:
allf = plain_allf = "{} {}"
# If Compact is selected, do it at the beginning
if "#" in spec:
spec = spec.replace("#", "")
obj = self.to_compact()
else:
obj = self
# the LaTeX siunitx code
if "Lx" in spec:
spec = spec.replace("Lx", "")
# TODO: add support for extracting options
opts = ""
ustr = siunitx_format_unit(obj.units)
allf = r"\SI[%s]{{{}}}{{{}}}" % opts
elif "H" in spec:
ustr = format(obj.units, spec)
assert ustr[:2] == r"\["
assert ustr[-2:] == r"\]"
ustr = ustr[2:-2]
allf = r"\[{}\ {}\]"
else:
ustr = format(obj.units, spec)
mspec = remove_custom_flags(spec)
if isinstance(self.magnitude, ndarray):
if "L" in spec:
mstr = ndarray_to_latex(obj.magnitude, mspec)
elif "H" in spec:
allf = r"\[{} {}\]"
# this is required to have the magnitude and unit in the same line
parts = ndarray_to_latex_parts(obj.magnitude, mspec)
if len(parts) > 1:
return "\n".join(allf.format(part, ustr) for part in parts)
mstr = parts[0]
else:
formatter = "{{:{}}}".format(mspec)
with printoptions(formatter={"float_kind": formatter.format}):
mstr = format(obj.magnitude).replace("\n", "")
else:
mstr = format(obj.magnitude, mspec).replace("\n", "")
if "L" in spec:
mstr = self._exp_pattern.sub(r"\1\\times 10^{\2\3}", mstr)
elif "H" in spec:
mstr = self._exp_pattern.sub(r"\1×10^{\2\3}", mstr)
elif "P" in spec:
m = self._exp_pattern.match(mstr)
if m:
exp = int(m.group(2) + m.group(3))
mstr = self._exp_pattern.sub(r"\1×10" + _pretty_fmt_exponent(exp), mstr)
if allf == plain_allf and ustr.startswith("1 /"):
# Write e.g. "3 / s" instead of "3 1 / s"
ustr = ustr[2:]
return allf.format(mstr, ustr).strip()
def _repr_pretty_(self, p, cycle):
if cycle:
super()._repr_pretty_(p, cycle)
else:
p.pretty(self.magnitude)
p.text(" ")
p.pretty(self.units)
def format_babel(self, spec="", **kwspec):
spec = spec or self.default_format
# standard cases
if "#" in spec:
spec = spec.replace("#", "")
obj = self.to_compact()
else:
obj = self
kwspec = dict(kwspec)
if "length" in kwspec:
kwspec["babel_length"] = kwspec.pop("length")
loc = kwspec.get("locale", self._REGISTRY.fmt_locale)
if loc is None:
raise ValueError("Provide a `locale` value to localize translation.")
kwspec["locale"] = babel_parse(loc)
kwspec["babel_plural_form"] = kwspec["locale"].plural_form(obj.magnitude)
return "{} {}".format(
format(obj.magnitude, remove_custom_flags(spec)),
obj.units.format_babel(spec, **kwspec),
).replace("\n", "")
@property
def magnitude(self):
"""Quantity's magnitude. Long form for `m`"""
return self._magnitude
@property
def m(self):
"""Quantity's magnitude. Short form for `magnitude`"""
return self._magnitude
[docs] def m_as(self, units):
"""Quantity's magnitude expressed in particular units.
Parameters
----------
units : pint.Quantity, str or dict
destination units
Returns
-------
"""
return self.to(units).magnitude
@property
def units(self):
"""Quantity's units. Long form for `u`"""
return self._REGISTRY.Unit(self._units)
@property
def u(self):
"""Quantity's units. Short form for `units`"""
return self._REGISTRY.Unit(self._units)
@property
def unitless(self):
""" """
return not bool(self.to_root_units()._units)
@property
def dimensionless(self):
""" """
tmp = self.to_root_units()
return not bool(tmp.dimensionality)
_dimensionality = None
@property
def dimensionality(self):
"""
Returns
-------
dict
Dimensionality of the Quantity, e.g. ``{length: 1, time: -1}``
"""
if self._dimensionality is None:
self._dimensionality = self._REGISTRY._get_dimensionality(self._units)
return self._dimensionality
[docs] def check(self, dimension):
"""Return true if the quantity's dimension matches passed dimension.
"""
return self.dimensionality == self._REGISTRY.get_dimensionality(dimension)
[docs] @classmethod
def from_list(cls, quant_list, units=None):
"""Transforms a list of Quantities into an numpy.array quantity.
If no units are specified, the unit of the first element will be used.
Same as from_sequence.
If units is not specified and list is empty, the unit cannot be determined
and a ValueError is raised.
Parameters
----------
quant_list : list of pint.Quantity
list of pint.Quantity
units : UnitsContainer, str or pint.Quantity
units of the physical quantity to be created (Default value = None)
Returns
-------
pint.Quantity
"""
return cls.from_sequence(quant_list, units=units)
[docs] @classmethod
def from_sequence(cls, seq, units=None):
"""Transforms a sequence of Quantities into an numpy.array quantity.
If no units are specified, the unit of the first element will be used.
If units is not specified and sequence is empty, the unit cannot be determined
and a ValueError is raised.
Parameters
----------
seq : sequence of pint.Quantity
sequence of pint.Quantity
units : UnitsContainer, str or pint.Quantity
units of the physical quantity to be created (Default value = None)
Returns
-------
pint.Quantity
"""
len_seq = len(seq)
if units is None:
if len_seq:
units = seq[0].u
else:
raise ValueError("Cannot determine units from empty sequence!")
a = np.empty(len_seq)
for i, seq_i in enumerate(seq):
a[i] = seq_i.m_as(units)
# raises DimensionalityError if incompatible units are used in the sequence
return cls(a, units)
@classmethod
def from_tuple(cls, tup):
return cls(tup[0], UnitsContainer(tup[1]))
def to_tuple(self):
return self.m, tuple(self._units.items())
def compatible_units(self, *contexts):
if contexts:
with self._REGISTRY.context(*contexts):
return self._REGISTRY.get_compatible_units(self._units)
return self._REGISTRY.get_compatible_units(self._units)
def _convert_magnitude_not_inplace(self, other, *contexts, **ctx_kwargs):
if contexts:
with self._REGISTRY.context(*contexts, **ctx_kwargs):
return self._REGISTRY.convert(self._magnitude, self._units, other)
return self._REGISTRY.convert(self._magnitude, self._units, other)
def _convert_magnitude(self, other, *contexts, **ctx_kwargs):
if contexts:
with self._REGISTRY.context(*contexts, **ctx_kwargs):
return self._REGISTRY.convert(self._magnitude, self._units, other)
return self._REGISTRY.convert(
self._magnitude,
self._units,
other,
inplace=is_duck_array_type(type(self._magnitude)),
)
[docs] def ito(self, other=None, *contexts, **ctx_kwargs):
"""Inplace rescale to different units.
Parameters
----------
other : pint.Quantity, str or dict
Destination units. (Default value = None)
*contexts : str or pint.Context
Contexts to use in the transformation.
**ctx_kwargs :
Values for the Context/s
"""
other = to_units_container(other, self._REGISTRY)
self._magnitude = self._convert_magnitude(other, *contexts, **ctx_kwargs)
self._units = other
return None
[docs] def to(self, other=None, *contexts, **ctx_kwargs):
"""Return Quantity rescaled to different units.
Parameters
----------
other : pint.Quantity, str or dict
destination units. (Default value = None)
*contexts : str or pint.Context
Contexts to use in the transformation.
**ctx_kwargs :
Values for the Context/s
Returns
-------
pint.Quantity
"""
other = to_units_container(other, self._REGISTRY)
magnitude = self._convert_magnitude_not_inplace(other, *contexts, **ctx_kwargs)
return self.__class__(magnitude, other)
[docs] def ito_root_units(self):
"""Return Quantity rescaled to root units."""
_, other = self._REGISTRY._get_root_units(self._units)
self._magnitude = self._convert_magnitude(other)
self._units = other
return None
[docs] def to_root_units(self):
"""Return Quantity rescaled to root units."""
_, other = self._REGISTRY._get_root_units(self._units)
magnitude = self._convert_magnitude_not_inplace(other)
return self.__class__(magnitude, other)
[docs] def ito_base_units(self):
"""Return Quantity rescaled to base units."""
_, other = self._REGISTRY._get_base_units(self._units)
self._magnitude = self._convert_magnitude(other)
self._units = other
return None
[docs] def to_base_units(self):
"""Return Quantity rescaled to base units."""
_, other = self._REGISTRY._get_base_units(self._units)
magnitude = self._convert_magnitude_not_inplace(other)
return self.__class__(magnitude, other)
[docs] def ito_reduced_units(self):
"""Return Quantity scaled in place to reduced units, i.e. one unit per
dimension. This will not reduce compound units (intentionally), nor
can it make use of contexts at this time.
"""
# shortcuts in case we're dimensionless or only a single unit
if self.dimensionless:
return self.ito({})
if len(self._units) == 1:
return None
newunits = self._units.copy()
# loop through individual units and compare to each other unit
# can we do better than a nested loop here?
for unit1, exp in self._units.items():
for unit2 in newunits:
if unit1 != unit2:
power = self._REGISTRY._get_dimensionality_ratio(unit1, unit2)
if power:
newunits = newunits.add(unit2, exp / power).remove([unit1])
break
return self.ito(newunits)
[docs] def to_reduced_units(self):
"""Return Quantity scaled in place to reduced units, i.e. one unit per
dimension. This will not reduce compound units (intentionally), nor
can it make use of contexts at this time.
"""
# can we make this more efficient?
newq = copy.copy(self)
newq.ito_reduced_units()
return newq
[docs] def to_compact(self, unit=None):
""""Return Quantity rescaled to compact, human-readable units.
To get output in terms of a different unit, use the unit parameter.
Example
-------
>>> import pint
>>> ureg = pint.UnitRegistry()
>>> (200e-9*ureg.s).to_compact()
<Quantity(200.0, 'nanosecond')>
>>> (1e-2*ureg('kg m/s^2')).to_compact('N')
<Quantity(10.0, 'millinewton')>
"""
if not isinstance(self.magnitude, numbers.Number):
msg = (
"to_compact applied to non numerical types "
"has an undefined behavior."
)
w = RuntimeWarning(msg)
warnings.warn(w, stacklevel=2)
return self
if (
self.unitless
or self.magnitude == 0
or math.isnan(self.magnitude)
or math.isinf(self.magnitude)
):
return self
SI_prefixes = {}
for prefix in self._REGISTRY._prefixes.values():
try:
scale = prefix.converter.scale
# Kludgy way to check if this is an SI prefix
log10_scale = int(math.log10(scale))
if log10_scale == math.log10(scale):
SI_prefixes[log10_scale] = prefix.name
except Exception:
SI_prefixes[0] = ""
SI_prefixes = sorted(SI_prefixes.items())
SI_powers = [item[0] for item in SI_prefixes]
SI_bases = [item[1] for item in SI_prefixes]
if unit is None:
unit = infer_base_unit(self)
q_base = self.to(unit)
magnitude = q_base.magnitude
units = list(q_base._units.items())
units_numerator = [a for a in units if a[1] > 0]
if len(units_numerator) > 0:
unit_str, unit_power = units_numerator[0]
else:
unit_str, unit_power = units[0]
if unit_power > 0:
power = int(math.floor(math.log10(abs(magnitude)) / unit_power / 3)) * 3
else:
power = int(math.ceil(math.log10(abs(magnitude)) / unit_power / 3)) * 3
prefix = SI_bases[bisect.bisect_left(SI_powers, power)]
new_unit_str = prefix + unit_str
new_unit_container = q_base._units.rename(unit_str, new_unit_str)
return self.to(new_unit_container)
# Mathematical operations
def __int__(self):
if self.dimensionless:
return int(self._convert_magnitude_not_inplace(UnitsContainer()))
raise DimensionalityError(self._units, "dimensionless")
def __float__(self):
if self.dimensionless:
return float(self._convert_magnitude_not_inplace(UnitsContainer()))
raise DimensionalityError(self._units, "dimensionless")
def __complex__(self):
if self.dimensionless:
return complex(self._convert_magnitude_not_inplace(UnitsContainer()))
raise DimensionalityError(self._units, "dimensionless")
@check_implemented
def _iadd_sub(self, other, op):
"""Perform addition or subtraction operation in-place and return the result.
Parameters
----------
other : pint.Quantity or any type accepted by :func:`_to_magnitude`
object to be added to / subtracted from self
op : function
operator function (e.g. operator.add, operator.isub)
"""
if not self._check(other):
# other not from same Registry or not a Quantity
try:
other_magnitude = _to_magnitude(
other, self.force_ndarray, self.force_ndarray_like
)
except PintTypeError:
raise
except TypeError:
return NotImplemented
if eq(other, 0, True):
# If the other value is 0 (but not Quantity 0)
# do the operation without checking units.
# We do the calculation instead of just returning the same
# value to enforce any shape checking and type casting due to
# the operation.
self._magnitude = op(self._magnitude, other_magnitude)
elif self.dimensionless:
self.ito(UnitsContainer())
self._magnitude = op(self._magnitude, other_magnitude)
else:
raise DimensionalityError(self._units, "dimensionless")
return self
if not self.dimensionality == other.dimensionality:
raise DimensionalityError(
self._units, other._units, self.dimensionality, other.dimensionality
)
# Next we define some variables to make if-clauses more readable.
self_non_mul_units = self._get_non_multiplicative_units()
is_self_multiplicative = len(self_non_mul_units) == 0
if len(self_non_mul_units) == 1:
self_non_mul_unit = self_non_mul_units[0]
other_non_mul_units = other._get_non_multiplicative_units()
is_other_multiplicative = len(other_non_mul_units) == 0
if len(other_non_mul_units) == 1:
other_non_mul_unit = other_non_mul_units[0]
# Presence of non-multiplicative units gives rise to several cases.
if is_self_multiplicative and is_other_multiplicative:
if self._units == other._units:
self._magnitude = op(self._magnitude, other._magnitude)
# If only self has a delta unit, other determines unit of result.
elif self._get_delta_units() and not other._get_delta_units():
self._magnitude = op(
self._convert_magnitude(other._units), other._magnitude
)
self._units = other._units
else:
self._magnitude = op(self._magnitude, other.to(self._units)._magnitude)
elif (
op == operator.isub
and len(self_non_mul_units) == 1
and self._units[self_non_mul_unit] == 1
and not other._has_compatible_delta(self_non_mul_unit)
):
if self._units == other._units:
self._magnitude = op(self._magnitude, other._magnitude)
else:
self._magnitude = op(self._magnitude, other.to(self._units)._magnitude)
self._units = self._units.rename(
self_non_mul_unit, "delta_" + self_non_mul_unit
)
elif (
op == operator.isub
and len(other_non_mul_units) == 1
and other._units[other_non_mul_unit] == 1
and not self._has_compatible_delta(other_non_mul_unit)
):
# we convert to self directly since it is multiplicative
self._magnitude = op(self._magnitude, other.to(self._units)._magnitude)
elif (
len(self_non_mul_units) == 1
# order of the dimension of offset unit == 1 ?
and self._units[self_non_mul_unit] == 1
and other._has_compatible_delta(self_non_mul_unit)
):
# Replace offset unit in self by the corresponding delta unit.
# This is done to prevent a shift by offset in the to()-call.
tu = self._units.rename(self_non_mul_unit, "delta_" + self_non_mul_unit)
self._magnitude = op(self._magnitude, other.to(tu)._magnitude)
elif (
len(other_non_mul_units) == 1
# order of the dimension of offset unit == 1 ?
and other._units[other_non_mul_unit] == 1
and self._has_compatible_delta(other_non_mul_unit)
):
# Replace offset unit in other by the corresponding delta unit.
# This is done to prevent a shift by offset in the to()-call.
tu = other._units.rename(other_non_mul_unit, "delta_" + other_non_mul_unit)
self._magnitude = op(self._convert_magnitude(tu), other._magnitude)
self._units = other._units
else:
raise OffsetUnitCalculusError(self._units, other._units)
return self
@check_implemented
def _add_sub(self, other, op):
"""Perform addition or subtraction operation and return the result.
Parameters
----------
other : pint.Quantity or any type accepted by :func:`_to_magnitude`
object to be added to / subtracted from self
op : function
operator function (e.g. operator.add, operator.isub)
"""
if not self._check(other):
# other not from same Registry or not a Quantity
if eq(other, 0, True):
# If the other value is 0 (but not Quantity 0)
# do the operation without checking units.
# We do the calculation instead of just returning the same
# value to enforce any shape checking and type casting due to
# the operation.
units = self._units
magnitude = op(
self._magnitude,
_to_magnitude(other, self.force_ndarray, self.force_ndarray_like),
)
elif self.dimensionless:
units = UnitsContainer()
magnitude = op(
self.to(units)._magnitude,
_to_magnitude(other, self.force_ndarray, self.force_ndarray_like),
)
else:
raise DimensionalityError(self._units, "dimensionless")
return self.__class__(magnitude, units)
if not self.dimensionality == other.dimensionality:
raise DimensionalityError(
self._units, other._units, self.dimensionality, other.dimensionality
)
# Next we define some variables to make if-clauses more readable.
self_non_mul_units = self._get_non_multiplicative_units()
is_self_multiplicative = len(self_non_mul_units) == 0
if len(self_non_mul_units) == 1:
self_non_mul_unit = self_non_mul_units[0]
other_non_mul_units = other._get_non_multiplicative_units()
is_other_multiplicative = len(other_non_mul_units) == 0
if len(other_non_mul_units) == 1:
other_non_mul_unit = other_non_mul_units[0]
# Presence of non-multiplicative units gives rise to several cases.
if is_self_multiplicative and is_other_multiplicative:
if self._units == other._units:
magnitude = op(self._magnitude, other._magnitude)
units = self._units
# If only self has a delta unit, other determines unit of result.
elif self._get_delta_units() and not other._get_delta_units():
magnitude = op(self._convert_magnitude(other._units), other._magnitude)
units = other._units
else:
units = self._units
magnitude = op(self._magnitude, other.to(self._units).magnitude)
elif (
op == operator.sub
and len(self_non_mul_units) == 1
and self._units[self_non_mul_unit] == 1
and not other._has_compatible_delta(self_non_mul_unit)
):
if self._units == other._units:
magnitude = op(self._magnitude, other._magnitude)
else:
magnitude = op(self._magnitude, other.to(self._units)._magnitude)
units = self._units.rename(self_non_mul_unit, "delta_" + self_non_mul_unit)
elif (
op == operator.sub
and len(other_non_mul_units) == 1
and other._units[other_non_mul_unit] == 1
and not self._has_compatible_delta(other_non_mul_unit)
):
# we convert to self directly since it is multiplicative
magnitude = op(self._magnitude, other.to(self._units)._magnitude)
units = self._units
elif (
len(self_non_mul_units) == 1
# order of the dimension of offset unit == 1 ?
and self._units[self_non_mul_unit] == 1
and other._has_compatible_delta(self_non_mul_unit)
):
# Replace offset unit in self by the corresponding delta unit.
# This is done to prevent a shift by offset in the to()-call.
tu = self._units.rename(self_non_mul_unit, "delta_" + self_non_mul_unit)
magnitude = op(self._magnitude, other.to(tu).magnitude)
units = self._units
elif (
len(other_non_mul_units) == 1
# order of the dimension of offset unit == 1 ?
and other._units[other_non_mul_unit] == 1
and self._has_compatible_delta(other_non_mul_unit)
):
# Replace offset unit in other by the corresponding delta unit.
# This is done to prevent a shift by offset in the to()-call.
tu = other._units.rename(other_non_mul_unit, "delta_" + other_non_mul_unit)
magnitude = op(self._convert_magnitude(tu), other._magnitude)
units = other._units
else:
raise OffsetUnitCalculusError(self._units, other._units)
return self.__class__(magnitude, units)
def __iadd__(self, other):
if isinstance(other, datetime.datetime):
return self.to_timedelta() + other
elif is_duck_array_type(type(self._magnitude)):
return self._iadd_sub(other, operator.iadd)
else:
return self._add_sub(other, operator.add)
def __add__(self, other):
if isinstance(other, datetime.datetime):
return self.to_timedelta() + other
else:
return self._add_sub(other, operator.add)
__radd__ = __add__
def __isub__(self, other):
if is_duck_array_type(type(self._magnitude)):
return self._iadd_sub(other, operator.isub)
else:
return self._add_sub(other, operator.sub)
def __sub__(self, other):
return self._add_sub(other, operator.sub)
def __rsub__(self, other):
if isinstance(other, datetime.datetime):
return other - self.to_timedelta()
else:
return -self._add_sub(other, operator.sub)
@check_implemented
@ireduce_dimensions
def _imul_div(self, other, magnitude_op, units_op=None):
"""Perform multiplication or division operation in-place and return the
result.
Parameters
----------
other : pint.Quantity or any type accepted by :func:`_to_magnitude`
object to be multiplied/divided with self
magnitude_op : function
operator function to perform on the magnitudes
(e.g. operator.mul)
units_op : function or None
operator function to perform on the units; if None,
*magnitude_op* is used (Default value = None)
Returns
-------
"""
if units_op is None:
units_op = magnitude_op
offset_units_self = self._get_non_multiplicative_units()
no_offset_units_self = len(offset_units_self)
if not self._check(other):
if not self._ok_for_muldiv(no_offset_units_self):
raise OffsetUnitCalculusError(self._units, getattr(other, "units", ""))
if len(offset_units_self) == 1:
if self._units[offset_units_self[0]] != 1 or magnitude_op not in [
operator.mul,
operator.imul,
]:
raise OffsetUnitCalculusError(
self._units, getattr(other, "units", "")
)
try:
other_magnitude = _to_magnitude(
other, self.force_ndarray, self.force_ndarray_like
)
except PintTypeError:
raise
except TypeError:
return NotImplemented
self._magnitude = magnitude_op(self._magnitude, other_magnitude)
self._units = units_op(self._units, UnitsContainer())
return self
if isinstance(other, self._REGISTRY.Unit):
other = 1 * other
if not self._ok_for_muldiv(no_offset_units_self):
raise OffsetUnitCalculusError(self._units, other._units)
elif no_offset_units_self == 1 and len(self._units) == 1:
self.ito_root_units()
no_offset_units_other = len(other._get_non_multiplicative_units())
if not other._ok_for_muldiv(no_offset_units_other):
raise OffsetUnitCalculusError(self._units, other._units)
elif no_offset_units_other == 1 and len(other._units) == 1:
other.ito_root_units()
self._magnitude = magnitude_op(self._magnitude, other._magnitude)
self._units = units_op(self._units, other._units)
return self
@check_implemented
@ireduce_dimensions
def _mul_div(self, other, magnitude_op, units_op=None):
"""Perform multiplication or division operation and return the result.
Parameters
----------
other : pint.Quantity or any type accepted by :func:`_to_magnitude`
object to be multiplied/divided with self
magnitude_op : function
operator function to perform on the magnitudes
(e.g. operator.mul)
units_op : function or None
operator function to perform on the units; if None,
*magnitude_op* is used (Default value = None)
Returns
-------
"""
if units_op is None:
units_op = magnitude_op
offset_units_self = self._get_non_multiplicative_units()
no_offset_units_self = len(offset_units_self)
if not self._check(other):
if not self._ok_for_muldiv(no_offset_units_self):
raise OffsetUnitCalculusError(self._units, getattr(other, "units", ""))
if len(offset_units_self) == 1:
if self._units[offset_units_self[0]] != 1 or magnitude_op not in [
operator.mul,
operator.imul,
]:
raise OffsetUnitCalculusError(
self._units, getattr(other, "units", "")
)
try:
other_magnitude = _to_magnitude(
other, self.force_ndarray, self.force_ndarray_like
)
except PintTypeError:
raise
except TypeError:
return NotImplemented
magnitude = magnitude_op(self._magnitude, other_magnitude)
units = units_op(self._units, UnitsContainer())
return self.__class__(magnitude, units)
if isinstance(other, self._REGISTRY.Unit):
other = 1 * other
new_self = self
if not self._ok_for_muldiv(no_offset_units_self):
raise OffsetUnitCalculusError(self._units, other._units)
elif no_offset_units_self == 1 and len(self._units) == 1:
new_self = self.to_root_units()
no_offset_units_other = len(other._get_non_multiplicative_units())
if not other._ok_for_muldiv(no_offset_units_other):
raise OffsetUnitCalculusError(self._units, other._units)
elif no_offset_units_other == 1 and len(other._units) == 1:
other = other.to_root_units()
magnitude = magnitude_op(new_self._magnitude, other._magnitude)
units = units_op(new_self._units, other._units)
return self.__class__(magnitude, units)
def __imul__(self, other):
if is_duck_array_type(type(self._magnitude)):
return self._imul_div(other, operator.imul)
else:
return self._mul_div(other, operator.mul)
def __mul__(self, other):
return self._mul_div(other, operator.mul)
__rmul__ = __mul__
def __matmul__(self, other):
# Use NumPy ufunc (existing since 1.16) for matrix multiplication
if version.parse(NUMPY_VER) >= version.parse("1.16"):
return np.matmul(self, other)
else:
return NotImplemented
__rmatmul__ = __matmul__
def __itruediv__(self, other):
if is_duck_array_type(type(self._magnitude)):
return self._imul_div(other, operator.itruediv)
else:
return self._mul_div(other, operator.truediv)
def __truediv__(self, other):
return self._mul_div(other, operator.truediv)
def __rtruediv__(self, other):
try:
other_magnitude = _to_magnitude(
other, self.force_ndarray, self.force_ndarray_like
)
except PintTypeError:
raise
except TypeError:
return NotImplemented
no_offset_units_self = len(self._get_non_multiplicative_units())
if not self._ok_for_muldiv(no_offset_units_self):
raise OffsetUnitCalculusError(self._units, "")
elif no_offset_units_self == 1 and len(self._units) == 1:
self = self.to_root_units()
return self.__class__(other_magnitude / self._magnitude, 1 / self._units)
__div__ = __truediv__
__rdiv__ = __rtruediv__
__idiv__ = __itruediv__
def __ifloordiv__(self, other):
if self._check(other):
self._magnitude //= other.to(self._units)._magnitude
elif self.dimensionless:
self._magnitude = self.to("")._magnitude // other
else:
raise DimensionalityError(self._units, "dimensionless")
self._units = UnitsContainer({})
return self
@check_implemented
def __floordiv__(self, other):
if self._check(other):
magnitude = self._magnitude // other.to(self._units)._magnitude
elif self.dimensionless:
magnitude = self.to("")._magnitude // other
else:
raise DimensionalityError(self._units, "dimensionless")
return self.__class__(magnitude, UnitsContainer({}))
@check_implemented
def __rfloordiv__(self, other):
if self._check(other):
magnitude = other._magnitude // self.to(other._units)._magnitude
elif self.dimensionless:
magnitude = other // self.to("")._magnitude
else:
raise DimensionalityError(self._units, "dimensionless")
return self.__class__(magnitude, UnitsContainer({}))
@check_implemented
def __imod__(self, other):
if not self._check(other):
other = self.__class__(other, UnitsContainer({}))
self._magnitude %= other.to(self._units)._magnitude
return self
@check_implemented
def __mod__(self, other):
if not self._check(other):
other = self.__class__(other, UnitsContainer({}))
magnitude = self._magnitude % other.to(self._units)._magnitude
return self.__class__(magnitude, self._units)
@check_implemented
def __rmod__(self, other):
if self._check(other):
magnitude = other._magnitude % self.to(other._units)._magnitude
return self.__class__(magnitude, other._units)
elif self.dimensionless:
magnitude = other % self.to("")._magnitude
return self.__class__(magnitude, UnitsContainer({}))
else:
raise DimensionalityError(self._units, "dimensionless")
@check_implemented
def __divmod__(self, other):
if not self._check(other):
other = self.__class__(other, UnitsContainer({}))
q, r = divmod(self._magnitude, other.to(self._units)._magnitude)
return (self.__class__(q, UnitsContainer({})), self.__class__(r, self._units))
@check_implemented
def __rdivmod__(self, other):
if self._check(other):
q, r = divmod(other._magnitude, self.to(other._units)._magnitude)
unit = other._units
elif self.dimensionless:
q, r = divmod(other, self.to("")._magnitude)
unit = UnitsContainer({})
else:
raise DimensionalityError(self._units, "dimensionless")
return (self.__class__(q, UnitsContainer({})), self.__class__(r, unit))
@check_implemented
def __ipow__(self, other):
if not is_duck_array_type(type(self._magnitude)):
return self.__pow__(other)
try:
_to_magnitude(other, self.force_ndarray, self.force_ndarray_like)
except PintTypeError:
raise
except TypeError:
return NotImplemented
else:
if not self._ok_for_muldiv:
raise OffsetUnitCalculusError(self._units)
if is_duck_array_type(type(getattr(other, "_magnitude", other))):
# arrays are refused as exponent, because they would create
# len(array) quantities of len(set(array)) different units
# unless the base is dimensionless.
if self.dimensionless:
if getattr(other, "dimensionless", False):
self._magnitude **= other.m_as("")
return self
elif not getattr(other, "dimensionless", True):
raise DimensionalityError(other._units, "dimensionless")
else:
self._magnitude **= other
return self
elif np.size(other) > 1:
raise DimensionalityError(
self._units,
"dimensionless",
extra_msg=". Quantity array exponents are only allowed if the "
"base is dimensionless",
)
if other == 1:
return self
elif other == 0:
self._units = UnitsContainer()
else:
if not self._is_multiplicative:
if self._REGISTRY.autoconvert_offset_to_baseunit:
self.ito_base_units()
else:
raise OffsetUnitCalculusError(self._units)
if getattr(other, "dimensionless", False):
other = other.to_base_units().magnitude
self._units **= other
elif not getattr(other, "dimensionless", True):
raise DimensionalityError(self._units, "dimensionless")
else:
self._units **= other
self._magnitude **= _to_magnitude(
other, self.force_ndarray, self.force_ndarray_like
)
return self
@check_implemented
def __pow__(self, other):
try:
_to_magnitude(other, self.force_ndarray, self.force_ndarray_like)
except PintTypeError:
raise
except TypeError:
return NotImplemented
else:
if not self._ok_for_muldiv:
raise OffsetUnitCalculusError(self._units)
if is_duck_array_type(type(getattr(other, "_magnitude", other))):
# arrays are refused as exponent, because they would create
# len(array) quantities of len(set(array)) different units
# unless the base is dimensionless.
if self.dimensionless:
if getattr(other, "dimensionless", False):
return self.__class__(self.m ** other.m_as(""))
elif not getattr(other, "dimensionless", True):
raise DimensionalityError(other._units, "dimensionless")
else:
return self.__class__(self.m ** other)
elif np.size(other) > 1:
raise DimensionalityError(
self._units,
"dimensionless",
extra_msg=". Quantity array exponents are only allowed if the "
"base is dimensionless",
)
new_self = self
if other == 1:
return self
elif other == 0:
exponent = 0
units = UnitsContainer()
else:
if not self._is_multiplicative:
if self._REGISTRY.autoconvert_offset_to_baseunit:
new_self = self.to_root_units()
else:
raise OffsetUnitCalculusError(self._units)
if getattr(other, "dimensionless", False):
exponent = other.to_root_units().magnitude
units = new_self._units ** exponent
elif not getattr(other, "dimensionless", True):
raise DimensionalityError(other._units, "dimensionless")
else:
exponent = _to_magnitude(
other, self.force_ndarray, self.force_ndarray_like
)
units = new_self._units ** exponent
magnitude = new_self._magnitude ** exponent
return self.__class__(magnitude, units)
@check_implemented
def __rpow__(self, other):
try:
_to_magnitude(other, self.force_ndarray, self.force_ndarray_like)
except PintTypeError:
raise
except TypeError:
return NotImplemented
else:
if not self.dimensionless:
raise DimensionalityError(self._units, "dimensionless")
if is_duck_array_type(type(self._magnitude)):
if np.size(self._magnitude) > 1:
raise DimensionalityError(self._units, "dimensionless")
new_self = self.to_root_units()
return other ** new_self._magnitude
def __abs__(self):
return self.__class__(abs(self._magnitude), self._units)
def __round__(self, ndigits=0):
return self.__class__(round(self._magnitude, ndigits=ndigits), self._units)
def __pos__(self):
return self.__class__(operator.pos(self._magnitude), self._units)
def __neg__(self):
return self.__class__(operator.neg(self._magnitude), self._units)
@check_implemented
def __eq__(self, other):
# We compare to the base class of Quantity because
# each Quantity class is unique.
if not isinstance(other, Quantity):
if eq(other, 0, True):
# Handle the special case in which we compare to zero
# (or an array of zeros)
if self._is_multiplicative:
# compare magnitude
return eq(self._magnitude, other, False)
else:
# compare the magnitude after converting the
# non-multiplicative quantity to base units
if self._REGISTRY.autoconvert_offset_to_baseunit:
return eq(self.to_base_units()._magnitude, other, False)
else:
raise OffsetUnitCalculusError(self._units)
return self.dimensionless and eq(
self._convert_magnitude(UnitsContainer()), other, False
)
if eq(self._magnitude, 0, True) and eq(other._magnitude, 0, True):
return self.dimensionality == other.dimensionality
if self._units == other._units:
return eq(self._magnitude, other._magnitude, False)
try:
return eq(
self._convert_magnitude_not_inplace(other._units),
other._magnitude,
False,
)
except DimensionalityError:
return False
@check_implemented
def __ne__(self, other):
out = self.__eq__(other)
if is_duck_array_type(type(out)):
return np.logical_not(out)
return not out
@check_implemented
def compare(self, other, op):
if not isinstance(other, self.__class__):
if self.dimensionless:
return op(self._convert_magnitude_not_inplace(UnitsContainer()), other)
elif eq(other, 0, True):
# Handle the special case in which we compare to zero
# (or an array of zeros)
if self._is_multiplicative:
# compare magnitude
return op(self._magnitude, other)
else:
# compare the magnitude after converting the
# non-multiplicative quantity to base units
if self._REGISTRY.autoconvert_offset_to_baseunit:
return op(self.to_base_units()._magnitude, other)
else:
raise OffsetUnitCalculusError(self._units)
else:
raise ValueError("Cannot compare Quantity and {}".format(type(other)))
if self._units == other._units:
return op(self._magnitude, other._magnitude)
if self.dimensionality != other.dimensionality:
raise DimensionalityError(
self._units, other._units, self.dimensionality, other.dimensionality
)
return op(self.to_root_units().magnitude, other.to_root_units().magnitude)
__lt__ = lambda self, other: self.compare(other, op=operator.lt)
__le__ = lambda self, other: self.compare(other, op=operator.le)
__ge__ = lambda self, other: self.compare(other, op=operator.ge)
__gt__ = lambda self, other: self.compare(other, op=operator.gt)
def __bool__(self):
# Only cast when non-ambiguous (when multiplicative unit)
if self._is_multiplicative:
return bool(self._magnitude)
else:
raise ValueError("Boolean value of Quantity with offset unit is ambiguous.")
__nonzero__ = __bool__
# NumPy function/ufunc support
__array_priority__ = 17
def __array_ufunc__(self, ufunc, method, *inputs, **kwargs):
if method != "__call__":
# Only handle ufuncs as callables
return NotImplemented
# Replicate types from __array_function__
types = set(
type(arg)
for arg in list(inputs) + list(kwargs.values())
if hasattr(arg, "__array_ufunc__")
)
return numpy_wrap("ufunc", ufunc, inputs, kwargs, types)
def __array_function__(self, func, types, args, kwargs):
return numpy_wrap("function", func, args, kwargs, types)
_wrapped_numpy_methods = ["flatten", "astype", "item"]
def _numpy_method_wrap(self, func, *args, **kwargs):
"""Convenience method to wrap on the fly NumPy ndarray methods taking
care of the units.
"""
# Set input units if needed
if func.__name__ in set_units_ufuncs:
self.__ito_if_needed(set_units_ufuncs[func.__name__][0])
value = func(*args, **kwargs)
# Set output units as needed
if func.__name__ in (
matching_input_copy_units_output_ufuncs
+ copy_units_output_ufuncs
+ self._wrapped_numpy_methods
):
output_unit = self._units
elif func.__name__ in set_units_ufuncs:
output_unit = set_units_ufuncs[func.__name__][1]
elif func.__name__ in matching_input_set_units_output_ufuncs:
output_unit = matching_input_set_units_output_ufuncs[func.__name__]
elif func.__name__ in op_units_output_ufuncs:
output_unit = get_op_output_unit(
op_units_output_ufuncs[func.__name__],
self.units,
list(args) + list(kwargs.values()),
self._magnitude.size,
)
else:
output_unit = None
if output_unit is not None:
return self.__class__(value, output_unit)
else:
return value
def __array__(self, t=None):
warnings.warn(
"The unit of the quantity is stripped when downcasting to ndarray.",
UnitStrippedWarning,
stacklevel=2,
)
return _to_magnitude(self._magnitude, force_ndarray=True)
def clip(self, first=None, second=None, out=None, **kwargs):
minimum = kwargs.get("min", first)
maximum = kwargs.get("max", second)
if minimum is None and maximum is None:
raise TypeError("clip() takes at least 3 arguments (2 given)")
if maximum is None and "min" not in kwargs:
minimum, maximum = maximum, minimum
kwargs = {"out": out}
if minimum is not None:
if isinstance(minimum, self.__class__):
kwargs["min"] = minimum.to(self).magnitude
elif self.dimensionless:
kwargs["min"] = minimum
else:
raise DimensionalityError("dimensionless", self._units)
if maximum is not None:
if isinstance(maximum, self.__class__):
kwargs["max"] = maximum.to(self).magnitude
elif self.dimensionless:
kwargs["max"] = maximum
else:
raise DimensionalityError("dimensionless", self._units)
return self.__class__(self.magnitude.clip(**kwargs), self._units)
def fill(self, value):
self._units = value._units
return self.magnitude.fill(value.magnitude)
def put(self, indices, values, mode="raise"):
if isinstance(values, self.__class__):
values = values.to(self).magnitude
elif self.dimensionless:
values = self.__class__(values, "").to(self)
else:
raise DimensionalityError("dimensionless", self._units)
self.magnitude.put(indices, values, mode)
@property
def real(self):
return self.__class__(self._magnitude.real, self._units)
@property
def imag(self):
return self.__class__(self._magnitude.imag, self._units)
@property
def T(self):
return self.__class__(self._magnitude.T, self._units)
@property
def flat(self):
for v in self._magnitude.flat:
yield self.__class__(v, self._units)
@property
def shape(self):
return self._magnitude.shape
@shape.setter
def shape(self, value):
self._magnitude.shape = value
def searchsorted(self, v, side="left", sorter=None):
if isinstance(v, self.__class__):
v = v.to(self).magnitude
elif self.dimensionless:
v = self.__class__(v, "").to(self)
else:
raise DimensionalityError("dimensionless", self._units)
return self.magnitude.searchsorted(v, side)
[docs] def dot(self, b):
"""Dot product of two arrays.
Wraps np.dot().
"""
return np.dot(self, b)
def __ito_if_needed(self, to_units):
if self.unitless and to_units == "radian":
return
self.ito(to_units)
def __len__(self):
return len(self._magnitude)
def __getattr__(self, item):
if item.startswith("__array_"):
# Handle array protocol attributes other than `__array__`
if ARRAY_FALLBACK:
# Deprecated fallback behavior
warnings.warn(
(
f"Array protocol attribute {item} accessed, with unit of the "
"Quantity being stripped. This attribute will become unavailable "
"in the next minor version of Pint. To make this potentially "
"incorrect attribute unavailable now, set the "
"PINT_ARRAY_PROTOCOL_FALLBACK environment variable to 0 before "
"importing Pint."
),
DeprecationWarning,
stacklevel=2,
)
if is_duck_array_type(type(self._magnitude)):
# Defer to magnitude, and don't catch any AttributeErrors
return getattr(self._magnitude, item)
else:
# If an `__array_` attribute is requested but the magnitude is not
# a duck array, we convert the magnitude to a numpy ndarray.
magnitude_as_array = _to_magnitude(
self._magnitude, force_ndarray=True
)
return getattr(magnitude_as_array, item)
else:
# TODO (next minor version): ARRAY_FALLBACK is removed and this becomes the standard behavior
raise AttributeError(f"Array protocol attribute {item} not available.")
elif item in HANDLED_UFUNCS or item in self._wrapped_numpy_methods:
magnitude_as_duck_array = _to_magnitude(
self._magnitude, force_ndarray_like=True
)
try:
attr = getattr(magnitude_as_duck_array, item)
return functools.partial(self._numpy_method_wrap, attr)
except AttributeError:
raise AttributeError(
f"NumPy method {item} not available on {type(magnitude_as_duck_array)}"
)
except TypeError as exc:
if "not callable" in str(exc):
raise AttributeError(
f"NumPy method {item} not callable on {type(magnitude_as_duck_array)}"
)
else:
raise exc
try:
return getattr(self._magnitude, item)
except AttributeError:
raise AttributeError(
"Neither Quantity object nor its magnitude ({}) "
"has attribute '{}'".format(self._magnitude, item)
)
def __getitem__(self, key):
try:
return type(self)(self._magnitude[key], self._units)
except PintTypeError:
raise
except TypeError:
raise TypeError(
"Neither Quantity object nor its magnitude ({})"
"supports indexing".format(self._magnitude)
)
def __setitem__(self, key, value):
try:
if math.isnan(value):
self._magnitude[key] = value
return
except TypeError:
pass
try:
if isinstance(value, self.__class__):
factor = self.__class__(
value.magnitude, value._units / self._units
).to_root_units()
else:
factor = self.__class__(value, self._units ** (-1)).to_root_units()
if isinstance(factor, self.__class__):
if not factor.dimensionless:
raise DimensionalityError(
value,
self.units,
extra_msg=". Assign a quantity with the same dimensionality "
"or access the magnitude directly as "
f"`obj.magnitude[{key}] = {value}`.",
)
self._magnitude[key] = factor.magnitude
else:
self._magnitude[key] = factor
except PintTypeError:
raise
except TypeError as exc:
raise TypeError(
f"Neither Quantity object nor its magnitude ({self._magnitude}) "
"supports indexing"
) from exc
def tolist(self):
units = self._units
return [
self.__class__(value, units).tolist()
if isinstance(value, list)
else self.__class__(value, units)
for value in self._magnitude.tolist()
]
# Measurement support
def plus_minus(self, error, relative=False):
if isinstance(error, self.__class__):
if relative:
raise ValueError("{} is not a valid relative error.".format(error))
error = error.to(self._units).magnitude
else:
if relative:
error = error * abs(self.magnitude)
return self._REGISTRY.Measurement(copy.copy(self.magnitude), error, self._units)
# methods/properties that help for math operations with offset units
@property
def _is_multiplicative(self):
"""Check if the Quantity object has only multiplicative units."""
return not self._get_non_multiplicative_units()
def _get_non_multiplicative_units(self):
"""Return a list of the of non-multiplicative units of the Quantity object."""
offset_units = [
unit
for unit in self._units.keys()
if not self._REGISTRY._units[unit].is_multiplicative
]
return offset_units
def _get_delta_units(self):
"""Return list of delta units ot the Quantity object."""
delta_units = [u for u in self._units.keys() if u.startswith("delta_")]
return delta_units
def _has_compatible_delta(self, unit):
""""Check if Quantity object has a delta_unit that is compatible with unit
"""
deltas = self._get_delta_units()
if "delta_" + unit in deltas:
return True
else: # Look for delta units with same dimension as the offset unit
offset_unit_dim = self._REGISTRY._units[unit].reference
for d in deltas:
if self._REGISTRY._units[d].reference == offset_unit_dim:
return True
return False
def _ok_for_muldiv(self, no_offset_units=None):
"""Checks if Quantity object can be multiplied or divided
"""
is_ok = True
if no_offset_units is None:
no_offset_units = len(self._get_non_multiplicative_units())
if no_offset_units > 1:
is_ok = False
if no_offset_units == 1:
if len(self._units) > 1:
is_ok = False
if (
len(self._units) == 1
and not self._REGISTRY.autoconvert_offset_to_baseunit
):
is_ok = False
if next(iter(self._units.values())) != 1:
is_ok = False
return is_ok
def to_timedelta(self):
return datetime.timedelta(microseconds=self.to("microseconds").magnitude)
_Quantity = Quantity
def build_quantity_class(registry):
class Quantity(_Quantity):
_REGISTRY = registry
return Quantity
