[1.1] Unit conversion error with astropy 4.2 #737
Description
With the new Astropy 4.2, Specutils (1.1 from PyPI) starts to show a number of failures in test_smoothing.py that look strange to me:
__________________________ test_smooth_custom_kernel ___________________________
self = <Quantity [1131.01333332, 1366.39097043, 1380.73344458, 1315.70807832,
1218.18529306, 1225.68833337, 1264.9...557.36062977, 1565.6571005 , 1519.2402814 ,
1489.30273208, 1434.86908964, 1202.1970936 , 874.83988599] mJy>
unit = Unit(dimensionless), equivalencies = []
def to_value(self, unit=None, equivalencies=[]):
"""…"""
if unit is None or unit is self.unit:
value = self.view(np.ndarray)
else:
unit = Unit(unit)
# We want a view if the unit does not change. One could check
# with "==", but that calculates the scale that we need anyway.
# TODO: would be better for `unit.to` to have an in-place flag.
try:
> scale = self.unit._to(unit)
/usr/lib/python3/dist-packages/astropy/units/quantity.py:738:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
self = Unit("mJy"), other = Unit(dimensionless)
def _to(self, other):
"""…"""
# …
if self is other:
return 1.0
# …
if isinstance(other, UnitBase):
self_decomposed = self.decompose()
other_decomposed = other.decompose()
# …
if(self_decomposed.powers == other_decomposed.powers and
all(self_base is other_base for (self_base, other_base)
in zip(self_decomposed.bases, other_decomposed.bases))):
return self_decomposed.scale / other_decomposed.scale
> raise UnitConversionError(
f"'{self!r}' is not a scaled version of '{other!r}'")
E astropy.units.core.UnitConversionError: 'Unit("mJy")' is not a scaled version of 'Unit(dimensionless)'
/usr/lib/python3/dist-packages/astropy/units/core.py:950: UnitConversionError
During handling of the above exception, another exception occurred:
simulated_spectra = <specutils.tests.spectral_examples.SpectraExamples object at 0x7f151d2c5c40>
def test_smooth_custom_kernel(simulated_spectra):
"""
Test CustomKernel smoothing with correct parmaeters.
"""
# Create the original spectrum
spec1 = simulated_spectra.s1_um_mJy_e1
flux_original = spec1.flux
# Create a custom kernel (some weird asymmetric-ness)
numpy_kernel = np.array([0.5, 1, 2, 0.5, 0.2])
numpy_kernel = numpy_kernel / np.sum(numpy_kernel)
custom_kernel = convolution.CustomKernel(numpy_kernel)
flux_smoothed_astropy = convolution.convolve(flux_original, custom_kernel)
# Calculate the custom smoothed
spec1_smoothed = convolution_smooth(spec1, custom_kernel)
> compare_flux(spec1_smoothed.flux.value, flux_smoothed_astropy, flux_original.value)
/usr/lib/python3/dist-packages/specutils/tests/test_smoothing.py:58:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
/usr/lib/python3/dist-packages/specutils/tests/test_smoothing.py:34: in compare_flux
assert np.allclose(flux_smooth1, flux_smooth2)
<__array_function__ internals>:5: in allclose
???
/usr/lib/python3/dist-packages/astropy/units/quantity.py:1509: in __array_function__
args, kwargs, unit, out = function_helper(*args, **kwargs)
/usr/lib/python3/dist-packages/astropy/units/quantity_helper/function_helpers.py:545: in close
(a, b), unit = _quantities2arrays(a, b, unit_from_first=True)
/usr/lib/python3/dist-packages/astropy/units/quantity_helper/function_helpers.py:345: in _quantities2arrays
arrays = tuple((q._to_own_unit(arg)) for arg in args)
/usr/lib/python3/dist-packages/astropy/units/quantity_helper/function_helpers.py:345: in <genexpr>
arrays = tuple((q._to_own_unit(arg)) for arg in args)
/usr/lib/python3/dist-packages/astropy/units/quantity.py:1339: in _to_own_unit
_value = value.to_value(self.unit)
/usr/lib/python3/dist-packages/astropy/units/quantity.py:741: in to_value
value = self._to_value(unit, equivalencies)
/usr/lib/python3/dist-packages/astropy/units/quantity.py:660: in _to_value
return self.unit.to(unit, self.view(np.ndarray),
/usr/lib/python3/dist-packages/astropy/units/core.py:987: in to
return self._get_converter(other, equivalencies=equivalencies)(value)
/usr/lib/python3/dist-packages/astropy/units/core.py:918: in _get_converter
raise exc
/usr/lib/python3/dist-packages/astropy/units/core.py:903: in _get_converter
return self._apply_equivalencies(
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
self = Unit("mJy"), unit = Unit("mJy"), other = Unit(dimensionless)
equivalencies = []
def _apply_equivalencies(self, unit, other, equivalencies):
"""
Internal function (used from `_get_converter`) to apply
equivalence pairs.
"""
def make_converter(scale1, func, scale2):
def convert(v):
return func(_condition_arg(v) / scale1) * scale2
return convert
for funit, tunit, a, b in equivalencies:
if tunit is None:
try:
ratio_in_funit = (other.decompose() /
unit.decompose()).decompose([funit])
return make_converter(ratio_in_funit.scale, a, 1.)
except UnitsError:
pass
else:
try:
scale1 = funit._to(unit)
scale2 = tunit._to(other)
return make_converter(scale1, a, scale2)
except UnitsError:
pass
try:
scale1 = tunit._to(unit)
scale2 = funit._to(other)
return make_converter(scale1, b, scale2)
except UnitsError:
pass
def get_err_str(unit):
unit_str = unit.to_string('unscaled')
physical_type = unit.physical_type
if physical_type != 'unknown':
unit_str = "'{}' ({})".format(
unit_str, physical_type)
else:
unit_str = f"'{unit_str}'"
return unit_str
unit_str = get_err_str(unit)
other_str = get_err_str(other)
> raise UnitConversionError(
"{} and {} are not convertible".format(
unit_str, other_str))
E astropy.units.core.UnitConversionError: 'mJy' (spectral flux density) and '' (dimensionless) are not convertible
/usr/lib/python3/dist-packages/astropy/units/core.py:886: UnitConversionError
Full test log is here. This happens in a number of test_smooth_* functions (test_smooth_box_good, test_smooth_box_good, test_smooth_gaussian_good, test_smooth_trapezoid_good).
I am not sure whether this is fixed in the current "master" branch; however I couldn't find a commit with an obvious name that fixes it.