def cfunits_conform(self, to_units, from_units=None):
"""
Conform value units in-place. If there are scale or offset parameters in the attribute dictionary, they will
be removed.
:param to_units: Target conform units.
:type to_units: str or units object
:param from_units: Overload source units.
:type from_units: str or units object
:raises: NoUnitsError
"""
if from_units is None and self.units is None:
raise NoUnitsError(self)
# Use overloaded value for source units.
from_units = self.cfunits if from_units is None else from_units
# Get the conform value before swapping the units. Conversion inside time dimensions may be negatively affected
# otherwise.
to_conform_value = self._get_to_conform_value_()
# Update the units attribute with the destination units. Do this before conversion to not enter recursion when
# setting the new value.
self.units = to_units
# Conform the units.
new_value = get_conformed_units(to_conform_value, from_units, to_units)
self._set_to_conform_value_(new_value)
# Let the data type load from the value array.
self._dtype = None
# Remove any compression attributes if present.
for remove in NETCDF_ATTRIBUTES_TO_REMOVE_ON_VALUE_CHANGE:
self.attrs.pop(remove, None)
def bounds(self, value):
self._bounds = get_none_or_2d(value)
if self._bounds is not None and self._original_units is not None:
are_units_equal = get_are_units_equal((self.units, self._original_units))
if not are_units_equal:
self._bounds = get_conformed_units(self._bounds, self._original_units, self.conform_units_to)
if value is not None:
self._validate_bounds_()
def cfunits_conform(self, *args, **kwargs):
# Get the from units before conforming the value. The units are changed in the value conform.
from_units = kwargs.get('from_units') or self.cfunits
# Store the original units to use for bounds conversion.
self._original_units = self.cfunits
# Conform the value.
AbstractSourcedVariable.cfunits_conform(self, *args, **kwargs)
# Conform the units
if self._bounds is not None:
self._bounds = get_conformed_units(self._bounds, from_units, args[0])
def test_get_field_with_overloaded_units(self):
rd = self.test_data.get_rd('cancm4_tas', kwds={'conform_units_to': 'celsius'})
preload = [False, True]
for pre in preload:
field = rd.get()
# Conform units argument needs to be attached to a field variable.
units_celsius = get_units_object('celsius')
self.assertEqual(field.variables['tas']._conform_units_to, units_celsius)
sub = field.get_time_region({'year': [2009], 'month': [5]})
if pre:
# If we wanted to load the data prior to subset then do so and manually perform the units conversion.
to_test = sub.variables['tas'].value.copy()
get_conformed_units(to_test, sub.variables['tas'].cfunits, units_celsius)
# Assert the conform attribute makes it though the subset
self.assertEqual(sub.variables['tas']._conform_units_to, units_celsius)
value = sub.variables['tas'].value
self.assertAlmostEqual(np.ma.mean(value), 5.921925206338206)
self.assertAlmostEqual(np.ma.median(value), 10.745431900024414)
if pre:
# Assert the manually converted array matches the loaded value.
self.assertNumpyAll(to_test, value)
def test_get_conformed_units(self):
value = np.array([5, 6, 7])
res = get_conformed_units(value, 'celsius', 'fahrenheit')
try:
import cf_units
# Test original values are unchanged.
self.assertEqual(np.mean(value), 6)
test_value = res
except ImportError:
import cfunits
# Test inplace conversion is used.
test_value = value
# Test values are conformed.
self.assertAlmostEqual(np.mean(test_value), 42.799999999999876)
def test_get_conformed_units(self):
value = np.array([5, 6, 7])
res = get_conformed_units(value, 'celsius', 'fahrenheit')
try:
import cf_units
# Test original values are unchanged.
self.assertEqual(np.mean(value), 6)
test_value = res
except ImportError:
import cfunits
# Test inplace conversion is used.
test_value = value
# Test values are conformed.
self.assertAlmostEqual(np.mean(test_value), 42.799999999999876)
