issues: 1234204439

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id node_id number title user state locked assignee milestone comments created_at updated_at closed_at author_association active_lock_reason draft pull_request body reactions performed_via_github_app state_reason repo type
1234204439 I_kwDOAMm_X85JkHcX 6600 `polyval` returns objects with different dimension order 22245117 closed 0     2 2022-05-12T16:07:50Z 2022-05-12T19:01:58Z 2022-05-12T19:01:58Z CONTRIBUTOR      

What is your issue?

I noticed that the dimension order of the object returned by the latest polyval (main, unreleased) is different compared to xarray<=2022.3.0. For example, the following code returns different results. ```python import xarray as xr import numpy as np

values = np.array( [ "2021-04-01T05:25:19.000000000", "2021-04-01T05:25:29.000000000", "2021-04-01T05:25:39.000000000", "2021-04-01T05:25:49.000000000", "2021-04-01T05:25:59.000000000", "2021-04-01T05:26:09.000000000", ], dtype="datetime64[ns]", ) azimuth_time = xr.DataArray( values, name="azimuth_time", coords={"azimuth_time": values - values[0]} )

polyfit_coefficients = xr.DataArray( [ [2.33333335e-43, 1.62499999e-43, 2.79166678e-43], [-1.15316667e-30, 1.49518518e-31, 9.08833333e-31], [-2.50272583e-18, -1.23851062e-18, -2.99098229e-18], [5.83965193e-06, -1.53321770e-07, -4.84640242e-06], [4.44739216e06, 1.45053974e06, 5.29960857e06], ], dims=("degree", "axis"), coords={"axis": [0, 1, 2], "degree": [4, 3, 2, 1, 0]}, )

ds_out = xr.polyval(azimuth_time.coords["azimuth_time"], polyfit_coefficients) print(ds_out.dims) xarray v2022.3.0 ('azimuth_time', 'axis')

xarray v2022.3.1.dev103+gfc282d59 ('axis', 'azimuth_time') ``` Is this the expected behaviour? If yes, is it worth mentioning this change in what's new/breaking changes?

cc: @headtr1ck

 
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