vertices_to_bounds does not work without coordinate #602
Description
This is an example which worked before v0.10.7
import xarray as xr
import cf_xarray as cfxr
bounds = xr.DataArray([[0.0, 0.5], [0.5, 1.0]], dims=("lat", "bounds"))
cfxr.bounds_to_vertices(bounds, "bounds")This results in
<xarray.DataArray (lat_vertices: 3)> Size: 24B
array([0. , 0.5, 1. ])
Dimensions without coordinates: lat_vertices
With the current main, i get:
ValueError: All core dimension orders must be aligned. Got orders: {}
I checked through the discussion in #579. I'm not sure if this was intentional to ensure correct ordering of bounds with respect to a corresponding coordinate. So this works:
import xarray as xr
import cf_xarray as cfxr
bounds = xr.DataArray(
[[0.0, 0.5], [0.5, 1.0]], dims=("lat", "bounds"), coords={"lat": [0.25, 0.75]}
)
cfxr.bounds_to_vertices(bounds, bounds_dim="bounds")and gives
<xarray.DataArray (lat_vertices: 3)> Size: 24B
array([0. , 0.5, 1. ])
Dimensions without coordinates: lat_vertices
full traceback
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
Cell In[2], [line 7](vscode-notebook-cell:?execution_count=2&line=7)
2 import cf_xarray as cfxr
4 bounds = xr.DataArray(
5 [[0.0, 0.5], [0.5, 1.0]], dims=("lat", "bounds")#, coords={"lat": [0.25, 0.[7](vscode-notebook-cell:?execution_count=2&line=7)5]}
6 )
----> 7 cfxr.bounds_to_vertices(bounds, bounds_dim="bounds")
File ~/python/packages/cf-xarray/cf_xarray/helpers.py:184, in bounds_to_vertices(bounds, bounds_dim, core_dims, order)
179 core_dim_coords = {
180 dim: bounds.coords[dim].values for dim in core_dims if dim in bounds.coords
181 }
182 core_dim_orders = _get_core_dim_orders(core_dim_coords)
--> [184](https://file+.vscode-resource.vscode-cdn.net/Users/Buntemey/python/packages/cf-xarray/doc/examples/~/python/packages/cf-xarray/cf_xarray/helpers.py:184) return xr.apply_ufunc(
185 _bounds_helper,
186 bounds,
187 input_core_dims=[core_dims + [bounds_dim]],
188 dask="parallelized",
189 kwargs={
190 "n_core_dims": n_core_dims,
191 "nbounds": nbounds,
192 "order": order,
193 "core_dim_orders": core_dim_orders,
194 },
195 output_core_dims=[output_core_dims],
196 dask_gufunc_kwargs=dict(output_sizes=output_sizes),
197 output_dtypes=[bounds.dtype],
198 )
File ~/miniforge3/envs/cf_xarray/lib/python3.12/site-packages/xarray/computation/apply_ufunc.py:1267, in apply_ufunc(func, input_core_dims, output_core_dims, exclude_dims, vectorize, join, dataset_join, dataset_fill_value, keep_attrs, kwargs, dask, output_dtypes, output_sizes, meta, dask_gufunc_kwargs, on_missing_core_dim, *args)
1265 # feed DataArray apply_variable_ufunc through apply_dataarray_vfunc
1266 elif any(isinstance(a, DataArray) for a in args):
-> [1267](https://file+.vscode-resource.vscode-cdn.net/Users/Buntemey/python/packages/cf-xarray/doc/examples/~/miniforge3/envs/cf_xarray/lib/python3.12/site-packages/xarray/computation/apply_ufunc.py:1267) return apply_dataarray_vfunc(
1268 variables_vfunc,
1269 *args,
1270 signature=signature,
1271 join=join,
1272 exclude_dims=exclude_dims,
1273 keep_attrs=keep_attrs,
1274 )
1275 # feed Variables directly through apply_variable_ufunc
1276 elif any(isinstance(a, Variable) for a in args):
File ~/miniforge3/envs/cf_xarray/lib/python3.12/site-packages/xarray/computation/apply_ufunc.py:310, in apply_dataarray_vfunc(func, signature, join, exclude_dims, keep_attrs, *args)
305 result_coords, result_indexes = build_output_coords_and_indexes(
306 args, signature, exclude_dims, combine_attrs=keep_attrs
307 )
309 data_vars = [getattr(a, "variable", a) for a in args]
--> [310](https://file+.vscode-resource.vscode-cdn.net/Users/Buntemey/python/packages/cf-xarray/doc/examples/~/miniforge3/envs/cf_xarray/lib/python3.12/site-packages/xarray/computation/apply_ufunc.py:310) result_var = func(*data_vars)
312 out: tuple[DataArray, ...] | DataArray
313 if signature.num_outputs > 1:
File ~/miniforge3/envs/cf_xarray/lib/python3.12/site-packages/xarray/computation/apply_ufunc.py:818, in apply_variable_ufunc(func, signature, exclude_dims, dask, output_dtypes, vectorize, keep_attrs, dask_gufunc_kwargs, *args)
813 elif vectorize:
814 func = _vectorize(
815 func, signature, output_dtypes=output_dtypes, exclude_dims=exclude_dims
816 )
--> [818](https://file+.vscode-resource.vscode-cdn.net/Users/Buntemey/python/packages/cf-xarray/doc/examples/~/miniforge3/envs/cf_xarray/lib/python3.12/site-packages/xarray/computation/apply_ufunc.py:818) result_data = func(*input_data)
820 if signature.num_outputs == 1:
821 result_data = (result_data,)
File ~/python/packages/cf-xarray/cf_xarray/helpers.py:284, in _bounds_helper(values, n_core_dims, nbounds, order, core_dim_orders)
281 vertex_vals = np.block([[bot_left, bot_right], [top_left, top_right]])
282 elif n_core_dims == 1 and nbounds == 2:
283 # Middle points case (1D lat/lon)
--> [284](https://file+.vscode-resource.vscode-cdn.net/Users/Buntemey/python/packages/cf-xarray/doc/examples/~/python/packages/cf-xarray/cf_xarray/helpers.py:284) vertex_vals = _get_ordered_vertices(values, core_dim_orders)
286 return vertex_vals
File ~/python/packages/cf-xarray/cf_xarray/helpers.py:330, in _get_ordered_vertices(bounds, core_dim_orders)
289 def _get_ordered_vertices(
290 bounds: np.ndarray, core_dim_orders: dict[str, str]
291 ) -> np.ndarray:
292 """
293 Convert a bounds array of shape (..., N, 2) or (N, 2) into a 1D array of vertices.
294
(...) 328 Array of vertices with shape (..., N+1) or (N+1,).
329 """
--> [330](https://file+.vscode-resource.vscode-cdn.net/Users/Buntemey/python/packages/cf-xarray/doc/examples/~/python/packages/cf-xarray/cf_xarray/helpers.py:330) order = _get_order_of_core_dims(core_dim_orders)
332 if _is_bounds_monotonic(bounds):
333 vertices = np.concatenate((bounds[..., :, 0], bounds[..., -1:, 1]), axis=-1)
File ~/python/packages/cf-xarray/cf_xarray/helpers.py:416, in _get_order_of_core_dims(core_dim_orders)
413 orders = set(core_dim_orders.values())
415 if len(orders) != 1:
--> [416](https://file+.vscode-resource.vscode-cdn.net/Users/Buntemey/python/packages/cf-xarray/doc/examples/~/python/packages/cf-xarray/cf_xarray/helpers.py:416) raise ValueError(
417 f"All core dimension orders must be aligned. Got orders: {core_dim_orders}"
418 )
420 order = next(iter(orders))
422 return order
ValueError: All core dimension orders must be aligned. Got orders: {}