conjugate not supported on Dask arrays

[joneuhauser]

What happened?

File ".venv/lib/python3.12/site-packages/xarray/core/duck_array_ops.py", line 110, in fail_on_dask_array_input
    raise NotImplementedError(msg % func_name)
NotImplementedError: 'conjugate' is not yet a valid method on dask arrays

What did you expect to happen?

.conjugate() should work on Dask arrays.

Minimal Complete Verifiable Example

import numpy as np
import dask.array as da
import xarray as xr

real = da.random.random((100, 100))
imag = da.random.random((100, 100))
z = real + 1j * imag

data = xr.DataArray(z, coords={'x': np.arange(100), 'y': np.arange(100)})

conj_data = data.conjugate()

MVCE confirmation

• Minimal example — the example is as focused as reasonably possible to demonstrate the underlying issue in xarray.
• Complete example — the example is self-contained, including all data and the text of any traceback.
• Verifiable example — the example copy & pastes into an IPython prompt or Binder notebook, returning the result.
• New issue — a search of GitHub Issues suggests this is not a duplicate.
• Recent environment — the issue occurs with the latest version of xarray and its dependencies.

Relevant log output

Anything else we need to know?

No response

Environment

INSTALLED VERSIONS

commit: None
python: 3.12.3 (main, Feb 4 2025, 14:48:35) [GCC 13.3.0]
python-bits: 64
OS: Linux
OS-release: 6.11.0-24-generic
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: None
LANG: de_DE.UTF-8
LOCALE: ('de_DE', 'UTF-8')
libhdf5: 1.14.6
libnetcdf: None

xarray: 2025.3.1
pandas: 2.2.3
numpy: 2.2.5
scipy: 1.15.2
netCDF4: None
pydap: None
h5netcdf: None
h5py: 3.13.0
zarr: 3.0.7
cftime: None
nc_time_axis: None
iris: None
bottleneck: None
dask: 2025.4.0
distributed: 2025.4.0
matplotlib: 3.10.1
cartopy: None
seaborn: None
numbagg: None
fsspec: 2025.3.2
cupy: None
pint: None
sparse: None
flox: None
numpy_groupies: None
setuptools: None
pip: 24.0
conda: None
pytest: None
mypy: None
IPython: 9.1.0
sphinx: None

[welcome]

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[kmuehlbauer]

Is there any reason you can't use conj-method? I'm not that versed in Python array API, but there only conj is referenced. Numpy has a notion of conjugate and conj, but Dask only has conj.

AFAIK xarray is trying to access both, hence the error when calling conjugate.

[joneuhauser]

Would you be interested in a PR forwarding conjugate to conj? It's the same method in numpy anyway, and the change would help towards the "drop-in replacement" of numpy with dask arrays.

[kmuehlbauer]

Would you be interested in a PR forwarding conjugate to conj?

Thanks for that. This part is not my area of expertise. Let's wait for others to chime in, what's the best way forward here.

[joneuhauser]

Opened a PR to discuss the change further.

[kmuehlbauer]

resolved by #10303