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uncertainquantity.py
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224 lines (189 loc) · 7.22 KB
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# -*- coding: utf-8 -*-
"""
"""
from __future__ import absolute_import
import sys
import numpy as np
from . import markup
from .quantity import Quantity, scale_other_units
from .registry import unit_registry
from .decorators import with_doc
class UncertainQuantity(Quantity):
# TODO: what is an appropriate value?
__array_priority__ = 22
def __new__(cls, data, units='', uncertainty=None, dtype='d', copy=True):
ret = Quantity.__new__(cls, data, units, dtype, copy)
# _uncertainty initialized to be dimensionless by __array_finalize__:
ret._uncertainty._dimensionality = ret._dimensionality
if uncertainty is not None:
ret.uncertainty = Quantity(uncertainty, ret._dimensionality)
elif isinstance(data, UncertainQuantity):
if copy or ret._dimensionality != uncertainty._dimensionality:
uncertainty = data.uncertainty.rescale(ret.units)
ret.uncertainty = uncertainty
return ret
@Quantity.units.setter
def units(self, units):
super(UncertainQuantity, self)._set_units(units)
self.uncertainty.units = self._dimensionality
@property
def _reference(self):
ret = super(UncertainQuantity, self)._reference.view(UncertainQuantity)
ret.uncertainty = self.uncertainty._reference
return ret
@property
def simplified(self):
ret = super(UncertainQuantity, self).simplified.view(UncertainQuantity)
ret.uncertainty = self.uncertainty.simplified
return ret
@property
def uncertainty(self):
return self._uncertainty
@uncertainty.setter
def uncertainty(self, uncertainty):
if not isinstance(uncertainty, Quantity):
uncertainty = Quantity(uncertainty, copy=False)
try:
assert self.shape == uncertainty.shape
except AssertionError:
raise ValueError('data and uncertainty must have identical shape')
if uncertainty._dimensionality != self._dimensionality:
uncertainty = uncertainty.rescale(self._dimensionality)
self._uncertainty = uncertainty
@property
def relative_uncertainty(self):
return self.uncertainty.magnitude/self.magnitude
@with_doc(Quantity.rescale, use_header=False)
def rescale(self, units):
cls = UncertainQuantity
ret = super(cls, self).rescale(units).view(cls)
ret.uncertainty = self.uncertainty.rescale(units)
return ret
def __array_finalize__(self, obj):
Quantity.__array_finalize__(self, obj)
self._uncertainty = getattr(
obj,
'uncertainty',
Quantity(
np.zeros(self.shape, self.dtype),
self._dimensionality,
copy=False
)
)
@with_doc(Quantity.__add__, use_header=False)
@scale_other_units
def __add__(self, other):
res = super(UncertainQuantity, self).__add__(other)
u = (self.uncertainty**2+other.uncertainty**2)**0.5
return UncertainQuantity(res, uncertainty=u, copy=False)
@with_doc(Quantity.__radd__, use_header=False)
@scale_other_units
def __radd__(self, other):
return self.__add__(other)
@with_doc(Quantity.__sub__, use_header=False)
@scale_other_units
def __sub__(self, other):
res = super(UncertainQuantity, self).__sub__(other)
u = (self.uncertainty**2+other.uncertainty**2)**0.5
return UncertainQuantity(res, uncertainty=u, copy=False)
@with_doc(Quantity.__rsub__, use_header=False)
@scale_other_units
def __rsub__(self, other):
if not isinstance(other, UncertainQuantity):
other = UncertainQuantity(other, copy=False)
return UncertainQuantity.__sub__(other, self)
@with_doc(Quantity.__mul__, use_header=False)
def __mul__(self, other):
res = super(UncertainQuantity, self).__mul__(other)
try:
sru = self.relative_uncertainty
oru = other.relative_uncertainty
ru = (sru**2+oru**2)**0.5
u = res.view(Quantity) * ru
except AttributeError:
other = np.array(other, copy=False, subok=True)
u = (self.uncertainty**2*other**2)**0.5
res._uncertainty = u
return res
@with_doc(Quantity.__rmul__, use_header=False)
def __rmul__(self, other):
return self.__mul__(other)
@with_doc(Quantity.__truediv__, use_header=False)
def __truediv__(self, other):
res = super(UncertainQuantity, self).__truediv__(other)
try:
sru = self.relative_uncertainty
oru = other.relative_uncertainty
ru = (sru**2+oru**2)**0.5
u = res.view(Quantity) * ru
except AttributeError:
other = np.array(other, copy=False, subok=True)
u = (self.uncertainty**2/other**2)**0.5
res._uncertainty = u
return res
@with_doc(Quantity.__rtruediv__, use_header=False)
def __rtruediv__(self, other):
temp = UncertainQuantity(
1/self.magnitude, self.dimensionality**-1,
self.relative_uncertainty/self.magnitude, copy=False
)
return other * temp
if sys.version_info[0] < 3:
__div__ = __truediv__
__rdiv__ = __rtruediv__
@with_doc(Quantity.__pow__, use_header=False)
def __pow__(self, other):
res = super(UncertainQuantity, self).__pow__(other)
res.uncertainty = res.view(Quantity) * other * self.relative_uncertainty
return res
@with_doc(Quantity.__getitem__, use_header=False)
def __getitem__(self, key):
return UncertainQuantity(
self.magnitude[key],
self._dimensionality,
self.uncertainty[key],
copy=False
)
@with_doc(Quantity.__repr__, use_header=False)
def __repr__(self):
return '%s(%s, %s, %s)'%(
self.__class__.__name__,
repr(self.magnitude),
self.dimensionality.string,
repr(self.uncertainty.magnitude)
)
@with_doc(Quantity.__str__, use_header=False)
def __str__(self):
if markup.config.use_unicode:
dims = self.dimensionality.unicode
else:
dims = self.dimensionality.string
s = '%s %s\n+/-%s (1 sigma)'%(
str(self.magnitude),
dims,
str(self.uncertainty)
)
if markup.config.use_unicode:
return s.replace('+/-', '±').replace(' sigma', 'σ')
return s
@with_doc(np.ndarray.sum)
def sum(self, axis=None, dtype=None, out=None):
return UncertainQuantity(
self.magnitude.sum(axis, dtype, out),
self.dimensionality,
(np.sum(self.uncertainty.magnitude**2, axis))**0.5,
copy=False
)
def __getstate__(self):
"""
Return the internal state of the quantity, for pickling
purposes.
"""
state = list(super(UncertainQuantity, self).__getstate__())
state.append(self._uncertainty)
return tuple(state)
def __setstate__(self, state):
(ver, shp, typ, isf, raw, units, sigma) = state
np.ndarray.__setstate__(self, (shp, typ, isf, raw))
self._dimensionality = units
self._uncertainty = sigma