def test_Regridder_init_fail():
"""Basic test for :meth:`~esmf_regrid.esmf_regridder.Regridder.__init__`."""
lon, lat, lon_bounds, lat_bounds = make_grid_args(2, 3)
src_grid = GridInfo(lon, lat, lon_bounds, lat_bounds)
lon, lat, lon_bounds, lat_bounds = make_grid_args(3, 2)
tgt_grid = GridInfo(lon, lat, lon_bounds, lat_bounds)
with pytest.raises(ValueError):
_ = Regridder(src_grid, tgt_grid, method="other")
def test_make_grid():
"""Basic test for :meth:`~esmf_regrid.esmf_regridder.GridInfo.make_esmf_field`."""
lon, lat, lon_bounds, lat_bounds = _make_small_grid_args()
grid = GridInfo(lon, lat, lon_bounds, lat_bounds)
esmf_grid = grid.make_esmf_field()
esmf_grid.data[:] = 0
relative_path = ("esmf_regridder", "test_GridInfo", "small_grid.txt")
fname = tests.get_result_path(relative_path)
with open(fname) as fi:
expected_repr = fi.read()
assert esmf_grid.__repr__() == expected_repr
def test_Regridder_init():
"""Basic test for :meth:`~esmf_regrid.esmf_regridder.Regridder.__init__`."""
lon, lat, lon_bounds, lat_bounds = make_grid_args(2, 3)
src_grid = GridInfo(lon, lat, lon_bounds, lat_bounds)
lon, lat, lon_bounds, lat_bounds = make_grid_args(3, 2)
tgt_grid = GridInfo(lon, lat, lon_bounds, lat_bounds)
rg = Regridder(src_grid, tgt_grid)
result = rg.weight_matrix
expected = _expected_weights()
assert np.allclose(result.toarray(), expected.toarray())
def _cube_to_GridInfo(cube):
# This is a simplified version of an equivalent function/method in PR #26.
# It is anticipated that this function will be replaced by the one in PR #26.
#
# Returns a GridInfo object describing the horizontal grid of the cube.
# This may be inherited from code written for the rectilinear regridding scheme.
lon = cube.coord("longitude")
lat = cube.coord("latitude")
# Ensure coords come from a proper grid.
assert isinstance(lon, iris.coords.DimCoord)
assert isinstance(lat, iris.coords.DimCoord)
# TODO: accommodate other x/y coords.
# TODO: perform checks on lat/lon.
# Checks may cover units, coord systems (e.g. rotated pole), contiguous bounds.
if cube.coord_system() is None:
crs = None
else:
crs = cube.coord_system().as_cartopy_crs()
return GridInfo(
lon.points,
lat.points,
_bounds_cf_to_simple_1d(lon.bounds),
_bounds_cf_to_simple_1d(lat.bounds),
crs=crs,
circular=lon.circular,
)
class TimeGridInfo:
def setup(self):
lon, lat, lon_bounds, lat_bounds = _make_small_grid_args()
self.grid = GridInfo(lon, lat, lon_bounds, lat_bounds)
def time_make_grid(self):
"""Basic test for :meth:`~esmf_regrid.esmf_regridder.GridInfo.make_esmf_field`."""
esmf_grid = self.grid.make_esmf_field()
esmf_grid.data[:] = 0
time_make_grid.version = 1
def test_esmpy_normalisation():
"""
Integration test for :meth:`~esmf_regrid.esmf_regridder.Regridder`.
Checks against ESMF to ensure results are consistent.
"""
src_data = np.array(
[
[1.0, 1.0],
[1.0, 0.0],
[1.0, 0.0],
],
)
src_mask = np.array(
[
[True, False],
[False, False],
[False, False],
]
)
src_array = ma.array(src_data, mask=src_mask)
lon, lat, lon_bounds, lat_bounds = make_grid_args(2, 3)
src_grid = GridInfo(lon, lat, lon_bounds, lat_bounds)
src_esmpy_grid = src_grid._make_esmf_grid()
src_esmpy_grid.add_item(ESMF.GridItem.MASK, staggerloc=ESMF.StaggerLoc.CENTER)
src_esmpy_grid.mask[0][...] = src_mask
src_field = ESMF.Field(src_esmpy_grid)
src_field.data[...] = src_data
lon, lat, lon_bounds, lat_bounds = make_grid_args(3, 2)
tgt_grid = GridInfo(lon, lat, lon_bounds, lat_bounds)
tgt_field = tgt_grid.make_esmf_field()
regridder = Regridder(src_grid, tgt_grid)
regridding_kwargs = {
"ignore_degenerate": True,
"regrid_method": ESMF.RegridMethod.CONSERVE,
"unmapped_action": ESMF.UnmappedAction.IGNORE,
"factors": True,
"src_mask_values": [1],
}
esmpy_fracarea_regridder = ESMF.Regrid(
src_field, tgt_field, norm_type=ESMF.NormType.FRACAREA, **regridding_kwargs
)
esmpy_dstarea_regridder = ESMF.Regrid(
src_field, tgt_field, norm_type=ESMF.NormType.DSTAREA, **regridding_kwargs
)
tgt_field_dstarea = esmpy_dstarea_regridder(src_field, tgt_field)
result_esmpy_dstarea = tgt_field_dstarea.data
result_dstarea = regridder.regrid(src_array, norm_type="dstarea")
assert ma.allclose(result_esmpy_dstarea, result_dstarea)
tgt_field_fracarea = esmpy_fracarea_regridder(src_field, tgt_field)
result_esmpy_fracarea = tgt_field_fracarea.data
result_fracarea = regridder.regrid(src_array, norm_type="fracarea")
assert ma.allclose(result_esmpy_fracarea, result_fracarea)
def _cube_to_GridInfo(cube, center=False, resolution=None):
# This is a simplified version of an equivalent function/method in PR #26.
# It is anticipated that this function will be replaced by the one in PR #26.
#
# Returns a GridInfo object describing the horizontal grid of the cube.
# This may be inherited from code written for the rectilinear regridding scheme.
lon, lat = cube.coord(axis="x"), cube.coord(axis="y")
# Checks may cover units, coord systems (e.g. rotated pole), contiguous bounds.
if cube.coord_system() is None:
crs = None
else:
crs = cube.coord_system().as_cartopy_crs()
londim, latdim = len(lon.shape), len(lat.shape)
assert londim == latdim
assert londim in (1, 2)
if londim == 1:
# Ensure coords come from a proper grid.
assert isinstance(lon, iris.coords.DimCoord)
assert isinstance(lat, iris.coords.DimCoord)
circular = lon.circular
# TODO: perform checks on lat/lon.
elif londim == 2:
assert cube.coord_dims(lon) == cube.coord_dims(lat)
assert lon.is_contiguous()
assert lat.is_contiguous()
# 2D coords must be AuxCoords, which do not have a circular attribute.
circular = False
lon_bound_array = lon.contiguous_bounds()
lon_bound_array = lon.units.convert(lon_bound_array, Unit("degrees"))
lat_bound_array = lat.contiguous_bounds()
lat_bound_array = lat.units.convert(lat_bound_array, Unit("degrees"))
if resolution is None:
grid_info = GridInfo(
lon.points,
lat.points,
lon_bound_array,
lat_bound_array,
crs=crs,
circular=circular,
center=center,
)
else:
grid_info = RefinedGridInfo(
lon_bound_array,
lat_bound_array,
crs=crs,
resolution=resolution,
)
return grid_info
def test_regrid_with_mesh():
"""Basic test for regridding with :meth:`~esmf_regrid.esmf_regridder.GridInfo.make_esmf_field`."""
mesh_args = _make_small_mesh_args()
mesh = MeshInfo(*mesh_args)
grid_args = make_grid_args(2, 3)
grid = GridInfo(*grid_args)
mesh_to_grid_regridder = Regridder(mesh, grid)
mesh_input = np.array([3, 2])
grid_output = mesh_to_grid_regridder.regrid(mesh_input)
expected_grid_output = np.array([
[2.671294712940605, 3.0],
[2.0885553467353097, 2.9222786250561574],
[2.0, 2.3397940801753307],
])
assert ma.allclose(expected_grid_output, grid_output)
grid_to_mesh_regridder = Regridder(grid, mesh)
grid_input = np.array([[0, 0], [1, 0], [2, 1]])
mesh_output = grid_to_mesh_regridder.regrid(grid_input)
expected_mesh_output = np.array([0.1408245341331448, 1.19732762534643])
assert ma.allclose(expected_mesh_output, mesh_output)
def _give_extra_dims(array):
result = np.stack([array, array + 1])
result = np.stack([result, result + 10, result + 100])
return result
extra_dim_mesh_input = _give_extra_dims(mesh_input)
extra_dim_grid_output = mesh_to_grid_regridder.regrid(extra_dim_mesh_input)
extra_dim_expected_grid_output = _give_extra_dims(expected_grid_output)
assert ma.allclose(extra_dim_expected_grid_output, extra_dim_grid_output)
extra_dim_grid_input = _give_extra_dims(grid_input)
extra_dim_mesh_output = grid_to_mesh_regridder.regrid(extra_dim_grid_input)
extra_dim_expected_mesh_output = _give_extra_dims(expected_mesh_output)
assert ma.allclose(extra_dim_expected_mesh_output, extra_dim_mesh_output)
def setup(self):
lon, lat, lon_bounds, lat_bounds = _make_small_grid_args()
self.grid = GridInfo(lon, lat, lon_bounds, lat_bounds)
def test_Regridder_regrid():
"""Basic test for :meth:`~esmf_regrid.esmf_regridder.Regridder.regrid`."""
lon, lat, lon_bounds, lat_bounds = make_grid_args(2, 3)
src_grid = GridInfo(lon, lat, lon_bounds, lat_bounds)
lon, lat, lon_bounds, lat_bounds = make_grid_args(3, 2)
tgt_grid = GridInfo(lon, lat, lon_bounds, lat_bounds)
# Set up the regridder with precomputed weights.
rg = Regridder(src_grid, tgt_grid, precomputed_weights=_expected_weights())
src_array = np.array([[1.0, 1.0], [1.0, 0.0], [1.0, 0.0]])
src_masked = ma.array(src_array, mask=np.array([[1, 0], [0, 0], [0, 0]]))
# Regrid with unmasked data.
result_nomask = rg.regrid(src_array)
expected_nomask = ma.array([
[1.0, 0.8336393373988409, 0.6674194025656824],
[1.0, 0.4999999999999997, 0.0],
])
assert ma.allclose(result_nomask, expected_nomask)
# Regrid with an masked array with no masked points.
result_ma_nomask = rg.regrid(ma.array(src_array))
assert ma.allclose(result_ma_nomask, expected_nomask)
# Regrid with a fully masked array.
result_fullmask = rg.regrid(ma.array(src_array, mask=True))
expected_fulmask = ma.array(np.zeros([2, 3]), mask=True)
assert ma.allclose(result_fullmask, expected_fulmask)
# Regrid with a masked array containing a masked point.
result_withmask = rg.regrid(src_masked)
expected_withmask = ma.array([
[0.9999999999999999, 0.7503444126612077, 0.6674194025656824],
[1.0, 0.4999999999999997, 0.0],
])
assert ma.allclose(result_withmask, expected_withmask)
# Regrid while setting mdtol.
result_half_mdtol = rg.regrid(src_masked, mdtol=0.5)
expected_half_mdtol = ma.array(expected_withmask,
mask=np.array([[1, 0, 1], [0, 0, 0]]))
assert ma.allclose(result_half_mdtol, expected_half_mdtol)
# Regrid with norm_type="dstarea".
result_dstarea = rg.regrid(src_masked, norm_type="dstarea")
expected_dstarea = ma.array([
[0.3325805974343169, 0.4999999999999999, 0.6674194025656823],
[0.9999999999999998, 0.499931367542066, 0.0],
])
assert ma.allclose(result_dstarea, expected_dstarea)
def _give_extra_dims(array):
result = np.stack([array, array + 1])
result = np.stack([result, result + 10, result + 100])
return result
# Regrid with multiple extra dimensions.
extra_dim_src = _give_extra_dims(src_array)
extra_dim_expected = _give_extra_dims(expected_nomask)
extra_dim_result = rg.regrid(extra_dim_src)
assert ma.allclose(extra_dim_result, extra_dim_expected)
# Regrid extra dimensions with different masks.
mixed_mask_src = ma.stack([src_array, src_masked])
mixed_mask_expected = np.stack([expected_nomask, expected_withmask])
mixed_mask_result = rg.regrid(mixed_mask_src)
assert ma.allclose(mixed_mask_result, mixed_mask_expected)
assert src_array.T.shape != src_array.shape
with pytest.raises(ValueError):
_ = rg.regrid(src_array.T)
with pytest.raises(ValueError):
_ = rg.regrid(src_masked, norm_type="INVALID")
def test_Regridder_init_small():
"""
Simplified test for :meth:`~esmf_regrid.esmf_regridder.Regridder.regrid`.
This test is designed to be simple enough to generate predictable weights.
With predictable weights it is easier to check that the weights are
associated with the correct indices.
"""
# The following ASCII visualisation describes the source and target grids
# and the indices which ESMF assigns to their cells.
# Analysis of the weights dict returned by ESMF confirms that this is
# indeed the indexing which ESMF assigns these grids.
#
# 30 +---+---+ +-------+
# | 3 | 6 | | |
# 20 +---+---+ | 2 |
# | 2 | 5 | | |
# 10 +---+---+ +-------+
# | 1 | 4 | | 1 |
# 0 +---+---+ +-------+
# 0 10 20 0 20
def _get_points(bounds):
points = (bounds[:-1] + bounds[1:]) / 2
return points
lon_bounds = np.array([0, 10, 20])
lat_bounds = np.array([0, 10, 20, 30])
lon, lat = _get_points(lon_bounds), _get_points(lat_bounds)
src_grid = GridInfo(lon, lat, lon_bounds, lat_bounds)
assert src_grid.shape == (3, 2)
assert src_grid._index_offset() == 1
lon_bounds = np.array([0, 20])
lat_bounds = np.array([0, 10, 30])
lon, lat = _get_points(lon_bounds), _get_points(lat_bounds)
tgt_grid = GridInfo(lon, lat, lon_bounds, lat_bounds)
assert tgt_grid.shape == (2, 1)
assert tgt_grid._index_offset() == 1
rg = Regridder(src_grid, tgt_grid)
result = rg.weight_matrix
weights_dict = {}
weights_dict["row_dst"] = (
np.array([1, 1, 1, 1, 2, 2, 2, 2], dtype=np.int32) -
src_grid._index_offset())
weights_dict["col_src"] = (
np.array([1, 2, 4, 5, 2, 3, 5, 6], dtype=np.int32) -
tgt_grid._index_offset())
# The following weights are calculated from grids on a sphere with great circles
# defining the lines. Because of this, weights are not exactly the same as they
# would be in euclidean geometry and there are some small additional weights
# where the cells would not ordinarily overlap in a euclidean grid.
weights_dict["weights"] = np.array([
0.4962897,
0.0037103, # Small weight due to using great circle lines
0.4962897,
0.0037103, # Small weight due to using great circle lines
0.25484249,
0.24076863,
0.25484249,
0.24076863,
])
expected_weights = scipy.sparse.csr_matrix(
(weights_dict["weights"], (weights_dict["row_dst"],
weights_dict["col_src"])))
assert np.allclose(result.toarray(), expected_weights.toarray())
def test_regrid_bilinear_with_mesh():
"""Basic test for regridding with :meth:`~esmf_regrid.esmf_regridder.GridInfo.make_esmf_field`."""
# We create a mesh with the following shape:
# 20 ,+ ,+ 4
# / | with nodes: / |
# 10 +' ,+ 1 +' ,+ 3
# | / | | / |
# 0 +---+ 0 +---+ 2
# 0 10
mesh_args = _make_small_mesh_args()
elem_coords = np.array([[5, 0], [5, 10]])
node_mesh = MeshInfo(*mesh_args, location="node")
face_mesh = MeshInfo(*mesh_args, elem_coords=elem_coords, location="face")
# We create a grid with the following shape:
# 20/3 +---+
# | |
# 10/3 +---+
# | |
# 0 +---+
# 0 10
grid_args = [ar * 2 for ar in make_grid_args(2, 3)]
grid = GridInfo(*grid_args, center=True)
mesh_to_grid_regridder = Regridder(node_mesh, grid, method="bilinear")
mesh_input = np.arange(5)
grid_output = mesh_to_grid_regridder.regrid(mesh_input)
# For a flat surface, we would expect the fractional part of these values
# to be either 1/3 or 2/3. Since the actual surface lies on a sphere, and
# due to the way ESMF calculates these values, the expected output is
# slightly different. It's worth noting that the finer the resolution, the
# closer these numbers are. Since the grids/meshes lie on coarse steps of
# about 10 degrees, we can expect most cases to behave more similarly to
# bilinear regridders on flat surfaces.
expected_grid_output = np.array([
[0.0, 2.0],
[0.6662902773937054, 2.6662902773105808],
[-1, 3.333709722689418],
])
expected_grid_mask = np.array([[0, 0], [0, 0], [1, 0]])
expected_grid_output = ma.array(expected_grid_output,
mask=expected_grid_mask)
assert ma.allclose(expected_grid_output, grid_output)
grid_to_mesh_regridder = Regridder(grid, node_mesh, method="bilinear")
grid_input = np.array([[0, 0], [1, 0], [2, 1]])
mesh_output = grid_to_mesh_regridder.regrid(grid_input)
expected_mesh_output = ma.array([0.0, 1.5, 0.0, 0.5, -1],
mask=[0, 0, 0, 0, 1])
assert ma.allclose(expected_mesh_output, mesh_output)
grid_to_face_mesh_regridder = Regridder(grid, face_mesh, method="bilinear")
grid_input_2 = np.array([[0, 0], [1, 0], [4, 1]])
face_mesh_output = grid_to_face_mesh_regridder.regrid(grid_input_2)
expected_face_mesh_output = np.array([0.0, 1.4888258584989558])
assert ma.allclose(expected_face_mesh_output, face_mesh_output)
def _give_extra_dims(array):
result = np.stack([array, array + 1])
result = np.stack([result, result + 10, result + 100])
return result
extra_dim_mesh_input = _give_extra_dims(mesh_input)
extra_dim_grid_output = mesh_to_grid_regridder.regrid(extra_dim_mesh_input)
extra_dim_expected_grid_output = _give_extra_dims(expected_grid_output)
assert ma.allclose(extra_dim_expected_grid_output, extra_dim_grid_output)
extra_dim_grid_input = _give_extra_dims(grid_input)
extra_dim_mesh_output = grid_to_mesh_regridder.regrid(extra_dim_grid_input)
extra_dim_expected_mesh_output = _give_extra_dims(expected_mesh_output)
assert ma.allclose(extra_dim_expected_mesh_output, extra_dim_mesh_output)