def test_unmodified_cell_methods(self):
"""Test that plugin leaves cell methods that are diagnostic name
agnostic unchanged."""
cell_methods = list(self.cube.cell_methods)
additional_cell_method_1 = CellMethod("sum", coords="longitude")
additional_cell_method_2 = CellMethod("sum",
coords="latitude",
comments="Kittens are great")
cell_methods.extend(
[additional_cell_method_1, additional_cell_method_2])
self.cube.cell_methods = cell_methods
cubelist = iris.cube.CubeList([self.cube, self.multiplier])
new_cube_name = "new_cube_name"
expected = [
CellMethod("sum", coords="time", comments=f"of {new_cube_name}"),
additional_cell_method_1,
additional_cell_method_2,
]
result = CubeMultiplier()(cubelist,
new_cube_name,
broadcast_to_threshold=True)
self.assertArrayEqual(result.cell_methods, expected)
def test_multiply_preserves_bounds(self):
"""Test specific case for precipitation type, where multiplying a
precipitation accumulation by a point-time probability of snow retains
the bounds on the original accumulation."""
validity_time = datetime(2015, 11, 19, 0)
time_bounds = [datetime(2015, 11, 18, 23), datetime(2015, 11, 19, 0)]
forecast_reference_time = datetime(2015, 11, 18, 22)
precip_accum = set_up_variable_cube(
np.full((2, 3, 3), 1.5, dtype=np.float32),
name="lwe_thickness_of_precipitation_amount",
units="mm",
time=validity_time,
time_bounds=time_bounds,
frt=forecast_reference_time,
)
snow_prob = set_up_variable_cube(
np.full(precip_accum.shape, 0.2, dtype=np.float32),
name="probability_of_snow",
units="1",
time=validity_time,
frt=forecast_reference_time,
)
result = CubeMultiplier()(
[precip_accum, snow_prob],
"lwe_thickness_of_snowfall_amount",
)
self.assertArrayAlmostEqual(result.data, np.full((2, 3, 3), 0.3))
self.assertArrayEqual(result.coord("time"), precip_accum.coord("time"))
def test_exception_for_single_entry_cubelist(self):
"""Test that the plugin raises an exception if a cubelist containing
only one cube is passed in."""
plugin = CubeMultiplier()
msg = "Expecting 2 or more cubes in cube_list"
cubelist = iris.cube.CubeList([self.cube1])
with self.assertRaisesRegex(ValueError, msg):
plugin.process(cubelist, "new_cube_name")
def process(
*cubes: cli.inputcube,
operation="+",
new_name=None,
use_midpoint=False,
check_metadata=False,
broadcast_to_threshold=False,
):
r"""Combine input cubes.
Combine the input cubes into a single cube using the requested operation.
The first cube in the input list provides the template for output metadata.
Args:
cubes (iris.cube.CubeList or list of iris.cube.Cube):
An iris CubeList to be combined.
operation (str):
An operation to use in combining input cubes. One of:
+, -, \*, add, subtract, multiply, min, max, mean
new_name (str):
New name for the resulting dataset.
use_midpoint (bool):
If False (not set), uses the upper bound as the new coordinate
point for expanded coordinates (eg time for accumulations / max in
period). If True, uses the mid-point.
check_metadata (bool):
If True, warn on metadata mismatch between inputs.
broadcast_to_threshold (bool):
If True, broadcast input cubes to the threshold coord prior to combining -
a threshold coord must already exist on the first input cube.
Returns:
result (iris.cube.Cube):
Returns a cube with the combined data.
"""
from improver.cube_combiner import CubeCombiner, CubeMultiplier
from iris.cube import CubeList
if not cubes:
raise TypeError("A cube is needed to be combined.")
if new_name is None:
new_name = cubes[0].name()
if operation == "*" or operation == "multiply":
result = CubeMultiplier()(
CubeList(cubes),
new_name,
broadcast_to_threshold=broadcast_to_threshold,
)
else:
result = CubeCombiner(operation)(
CubeList(cubes),
new_name,
use_midpoint=use_midpoint,
)
return result
def test_error_broadcast_coord_is_auxcoord(self):
"""Test that plugin throws an error if asked to broadcast to a threshold coord
that already exists on later cubes"""
cube = self.cube4[:, 0, ...].copy()
cube.data = np.ones_like(cube.data)
cubelist = iris.cube.CubeList([self.cube4.copy(), cube])
msg = "Cannot broadcast to coord threshold as it already exists as an AuxCoord"
with self.assertRaisesRegex(TypeError, msg):
CubeMultiplier()(cubelist, "new_cube_name", broadcast_to_threshold=True)
def test_error_broadcast_coord_is_auxcoord(self):
"""Test that plugin throws an error if asked to broadcast to a threshold coord
that already exists on later cubes"""
self.multiplier.add_aux_coord(self.threshold_aux)
cubelist = iris.cube.CubeList([self.cube.copy(), self.multiplier])
msg = "Cannot broadcast to coord threshold as it already exists as an AuxCoord"
with self.assertRaisesRegex(TypeError, msg):
CubeMultiplier(broadcast_to_threshold=True)(cubelist,
"new_cube_name")
def test_error_broadcast_coord_not_found(self):
"""Test that plugin throws an error if asked to broadcast to a threshold coord
that is not present on the first cube"""
cubelist = iris.cube.CubeList([self.multiplier, self.cube.copy()])
msg = (
r"Cannot find coord threshold in "
r"<iris 'Cube' of "
r"probability_of_lwe_thickness_of_precipitation_amount_above_threshold / \(1\) "
r"\(realization: 3; latitude: 2; longitude: 2\)> to broadcast to")
with self.assertRaisesRegex(CoordinateNotFoundError, msg):
CubeMultiplier(broadcast_to_threshold=True)(cubelist,
"new_cube_name")
def test_vicinity_names(self):
"""Test plugin names the cube and threshold coordinate correctly for a
vicinity diagnostic"""
input = "lwe_thickness_of_precipitation_amount_in_vicinity"
output = "thickness_of_rainfall_amount_in_vicinity"
self.cube.rename(f"probability_of_{input}_above_threshold")
cubelist = iris.cube.CubeList([self.cube.copy(), self.multiplier])
result = CubeMultiplier(broadcast_to_threshold=True)(cubelist, output)
self.assertEqual(result.name(),
f"probability_of_{output}_above_threshold")
self.assertEqual(
result.coord(var_name="threshold").name(),
"thickness_of_rainfall_amount")
def test_update_cell_methods(self):
"""Test that plugin updates cell methods where required when a new
diagnostic name is provided."""
cubelist = iris.cube.CubeList([self.cube, self.multiplier])
new_cube_name = "new_cube_name"
expected = CellMethod("sum",
coords="time",
comments=f"of {new_cube_name}")
result = CubeMultiplier(broadcast_to_threshold=True)(cubelist,
new_cube_name)
self.assertEqual(result.cell_methods[0], expected)
def test_error_broadcast_coord_not_found(self):
"""Test that plugin throws an error if asked to broadcast to a threshold coord
that is not present on the first cube"""
cube = self.cube4[:, 0, ...].copy()
cube.data = np.ones_like(cube.data)
cube.remove_coord("lwe_thickness_of_precipitation_amount")
cubelist = iris.cube.CubeList([cube, self.cube4.copy()])
msg = (
"Cannot find coord threshold in "
"<iris 'Cube' of probability_of_lwe_thickness_of_precipitation_amount_above_threshold / \(1\) "
"\(realization: 3; latitude: 2; longitude: 2\)> to broadcast to"
)
with self.assertRaisesRegex(CoordinateNotFoundError, msg):
CubeMultiplier()(cubelist, "new_cube_name", broadcast_to_threshold=True)
def test_vicinity_names(self):
"""Test plugin names the cube and threshold coordinate correctly for a
vicinity diagnostic"""
input = "lwe_thickness_of_precipitation_amount_in_vicinity"
output = "thickness_of_rainfall_amount_in_vicinity"
self.cube4.rename(f"probability_of_{input}_above_threshold")
cube = self.cube4[:, 0, ...].copy()
cube.data = np.ones_like(cube.data)
cube.remove_coord("lwe_thickness_of_precipitation_amount")
cubelist = iris.cube.CubeList([self.cube4.copy(), cube])
input_copy = deepcopy(cubelist)
result = CubeMultiplier()(cubelist, output, broadcast_to_threshold=True)
self.assertEqual(result.name(), f"probability_of_{output}_above_threshold")
self.assertEqual(
result.coord(var_name="threshold").name(), "thickness_of_rainfall_amount"
)
def test_broadcast_coord(self):
"""Test that plugin broadcasts to threshold coord without changing inputs.
Using the broadcast_to_coords argument including a value of "threshold"
will result in the returned cube maintaining the probabilistic elements
of the name of the first input cube."""
cubelist = iris.cube.CubeList([self.cube.copy(), self.multiplier])
input_copy = deepcopy(cubelist)
result = CubeMultiplier(broadcast_to_threshold=True)(cubelist,
"new_cube_name")
self.assertIsInstance(result, Cube)
self.assertEqual(result.name(),
"probability_of_new_cube_name_above_threshold")
self.assertEqual(
result.coord(var_name="threshold").name(), "new_cube_name")
self.assertArrayAlmostEqual(result.data, self.cube.data)
self.assertCubeListEqual(input_copy, cubelist)
def test_broadcast_coord(self):
"""Test that plugin broadcasts to threshold coord without changing inputs.
Using the broadcast_to_coords argument including a value of "threshold"
will result in the returned cube maintaining the probabilistic elements
of the name of the first input cube."""
cube = self.cube4[:, 0, ...].copy()
cube.data = np.ones_like(cube.data)
cube.remove_coord("lwe_thickness_of_precipitation_amount")
cubelist = iris.cube.CubeList([self.cube4.copy(), cube])
input_copy = deepcopy(cubelist)
result = CubeMultiplier()(
cubelist, "new_cube_name", broadcast_to_threshold=True
)
self.assertIsInstance(result, Cube)
self.assertEqual(result.name(), "probability_of_new_cube_name_above_threshold")
self.assertEqual(result.coord(var_name="threshold").name(), "new_cube_name")
self.assertArrayAlmostEqual(result.data, self.cube4.data)
self.assertCubeListEqual(input_copy, cubelist)