def calculate(self, values, threshold=15):
"""
Return the number of freeze-thaw transitions. A value of 2 corresponds
to a complete cycle (frozen-thawed-frozen).
:param threshold: The number of degree-days above or below the freezing point after which the ground is considered frozen or thawed.
"""
assert (len(values.shape) == 3)
# Check temporal resolution
t = self.field['time'].get_value()[:2]
step = t[1] - t[0]
if type(step) == dt.timedelta:
assert step == dt.timedelta(days=1)
else:
if self.field['time'].units.startswith('days'):
assert step == 1
else:
raise NotImplementedError
# Unit conversion
units = self.field.data_variables[0].units
if get_are_units_equal_by_string_or_cfunits(units, 'C',
try_cfunits=env.USE_CFUNITS):
tas = values
elif get_are_units_equal_by_string_or_cfunits(units, 'K',
try_cfunits=env.USE_CFUNITS):
tas = values - 273.15
out = np.apply_along_axis(freezethaw1d, 0, tas, threshold=threshold)
return np.ma.masked_invalid(out)
def calculate(self, values, threshold=15):
"""
Return the number of freeze-thaw transitions. A value of 2 corresponds
to a complete cycle (frozen-thawed-frozen).
:param threshold: The number of degree-days above or below the freezing point after which the ground is considered frozen or thawed.
"""
assert (len(values.shape) == 3)
# Check temporal resolution
t = self.field['time'].get_value()[:2]
step = t[1] - t[0]
if type(step) == dt.timedelta:
assert step == dt.timedelta(days=1)
else:
if self.field['time'].units.startswith('days'):
assert step == 1
else:
raise NotImplementedError
# Unit conversion
units = self.field.data_variables[0].units
if get_are_units_equal_by_string_or_cfunits(
units, 'C', try_cfunits=env.USE_CFUNITS):
tas = values
elif get_are_units_equal_by_string_or_cfunits(
units, 'K', try_cfunits=env.USE_CFUNITS):
tas = values - 273.15
out = np.apply_along_axis(freezethaw1d, 0, tas, threshold=threshold)
return np.ma.masked_invalid(out)
def validate_units(self, variable):
if self.required_units is not None:
matches = [get_are_units_equal_by_string_or_cfunits(variable.units, target, try_cfunits=env.USE_CFUNITS) \
for target in self.required_units]
if not any(matches):
raise UnitsValidationError(variable, self.required_units,
self.key)
def validate_units(self, variable):
if self.required_units is not None:
matches = [
get_are_units_equal_by_string_or_cfunits(variable.units, target, try_cfunits=True)
for target in self.required_units
]
if not any(matches):
raise (UnitsValidationError(variable, self.required_units, self.key))
def test_get_are_units_equal_by_string_or_cfunits(self):
_try_cfunits = [True, False]
source = 'K'
target = 'K'
for try_cfunits in _try_cfunits:
match = get_are_units_equal_by_string_or_cfunits(source, target, try_cfunits=try_cfunits)
self.assertTrue(match)
source = 'K'
target = 'Kelvin'
for try_cfunits in _try_cfunits:
match = get_are_units_equal_by_string_or_cfunits(source, target, try_cfunits=try_cfunits)
# cfunits.Units will allow comparison of abbreviated and full name form while string comparison will not
if try_cfunits:
self.assertTrue(match)
else:
self.assertFalse(match)
def test_get_are_units_equal_by_string_or_cfunits(self):
_try_cfunits = [True, False]
source = 'K'
target = 'K'
for try_cfunits in _try_cfunits:
match = get_are_units_equal_by_string_or_cfunits(source, target, try_cfunits=try_cfunits)
self.assertTrue(match)
source = 'K'
target = 'Kelvin'
for try_cfunits in _try_cfunits:
match = get_are_units_equal_by_string_or_cfunits(source, target, try_cfunits=try_cfunits)
# CF units packages will allow comparison of abbreviations.
if try_cfunits:
self.assertTrue(match)
else:
self.assertFalse(match)
def validate_units(self):
if self.required_units is not None:
for required_variable in self.required_variables:
alias_variable = self.parms[required_variable]
variable = self.field[alias_variable]
source = variable.units
target = self.required_units[required_variable]
match = get_are_units_equal_by_string_or_cfunits(source, target, try_cfunits=env.USE_CFUNITS)
if not match:
raise UnitsValidationError(variable, target, self.key)
def validate_units(self):
if self.required_units is not None:
for required_variable in self.required_variables:
alias_variable = self.parms[required_variable]
variable = self.field.variables[alias_variable]
source = variable.units
target = self.required_units[required_variable]
match = get_are_units_equal_by_string_or_cfunits(source, target, try_cfunits=True)
if match == False:
raise UnitsValidationError(variable, target, self.key)
def test_get_are_units_equal_by_string_or_cfunits(self):
_try_cfunits = [True, False]
source = 'K'
target = 'K'
for try_cfunits in _try_cfunits:
match = get_are_units_equal_by_string_or_cfunits(
source, target, try_cfunits=try_cfunits)
self.assertTrue(match)
source = 'K'
target = 'Kelvin'
for try_cfunits in _try_cfunits:
match = get_are_units_equal_by_string_or_cfunits(
source, target, try_cfunits=try_cfunits)
# CF units packages will allow comparison of abbreviations.
if try_cfunits:
self.assertTrue(match)
else:
self.assertFalse(match)
def calculate(self, values, threshold=15):
"""
Return the number of freeze-thaw transitions. A value of 2 corresponds
to a complete cycle (frozen-thawed-frozen).
:param threshold: The number of degree-days above or below the freezing point after which the ground is considered frozen or thawed.
"""
assert (len(values.shape) == 3)
# Check temporal resolution
t = self.field['time'].get_value()[:2]
step = t[1] - t[0]
assert step == dt.timedelta(days=1)
# Unit conversion
units = self.field.data_variables[0].units
if get_are_units_equal_by_string_or_cfunits(
units, 'C', try_cfunits=env.USE_CFUNITS):
tas = values
elif get_are_units_equal_by_string_or_cfunits(
units, 'K', try_cfunits=env.USE_CFUNITS):
tas = values - 273.15
# Storage array for count
shp_out = values.shape[-2:]
out = np.zeros(shp_out, dtype=int).flatten()
# Actual computations, grid cell by grid cell.
for ii, (rowidx, colidx) in enumerate(
iter_array(values[0, :, :], use_mask=True)):
x = tas[:, rowidx, colidx].reshape(-1)
out[ii] = freezethaw1d(x, threshold)
out.resize(shp_out)
# update the output mask. this only applies to geometries so pick the
# first masked time field
out = np.ma.array(out, mask=values.mask[0, :, :])
return out
