issues

I haven't looked at this too closely but it appears that this is a way to save MultiIndexed datasets to netCDF. So we may be able to do sparse -> multiindex -> netCDF

http://cfconventions.org/Data/cf-conventions/cf-conventions-1.8/cf-conventions.html#compression-by-gathering

cc @fujiisoup

Is your feature request related to a problem?

Shall we support opt_einsum as an optional backend for xr.dot?

opt_einsum.contract is a drop-in replacement for np.einsum so this monkey-patch works today xr.core.duck_array_ops.einsum = opt_einsum.contract

Describe the solution you'd like

Add a backend kwarg with options "numpy" and "opt_einsum", with the default being "numpy"

Describe alternatives you've considered

We could create a new package but it seems a bit silly.

Additional context

No response

What is your issue?

Here's the output from the Scientific Python Repo Review tool.

There's an online version here.

On mac I run pipx run 'sp-repo-review[cli]' --format html --show err gh:pydata/xarray@main | pbcopy

A lot of these seem fairly easy to fix. I'll note that there's a large number of mypy config suggestions.

General

• Detected build backend: setuptools.build_meta
• Detected license(s): Apache Software License

<table> <tr><th>?</th><th>Name</th><th>Description</th></tr> <tr style="color: red;"> <td>❌</td> <td>PY007</td> <td> Supports an easy task runner (nox or tox)

Projects must have a noxfile.py or tox.ini to encourage new contributors.

</td> </tr> </table>

PyProject

See https://github.com/pydata/xarray/issues/8239#issuecomment-1739363809

<table> <tr><th>?</th><th>Name</th><th>Description</th></tr> <tr style="color: red;"> <td>❌</td> <td>PP305</td> <td> Specifies xfail_strict

xfail_strict should be set. You can manually specify if a check should be strict when setting each xfail.

[tool.pytest.ini_options]
xfail_strict = true

</td> </tr> <tr style="color: red;"> <td>❌</td> <td>PP308</td> <td> Specifies useful pytest summary

-ra should be in addopts = [...] (print summary of all fails/errors).

[tool.pytest.ini_options]
addops = ["-ra", "--strict-config", "--strict-markers"]

</td> </tr> </table>

Pre-commit

<table> <tr><th>?</th><th>Name</th><th>Description</th></tr> <tr style="color: red;"> <td>❌</td> <td>PC110</td> <td> Uses black

Use https://github.com/psf/black-pre-commit-mirror instead of https://github.com/psf/black in .pre-commit-config.yaml

</td> </tr> <tr style="color: red;"> <td>❌</td> <td>PC160</td> <td> Uses codespell

Must have https://github.com/codespell-project/codespell repo in .pre-commit-config.yaml

</td> </tr> <tr style="color: red;"> <td>❌</td> <td>PC170</td> <td> Uses PyGrep hooks (only needed if RST present)

Must have https://github.com/pre-commit/pygrep-hooks repo in .pre-commit-config.yaml

</td> </tr> <tr style="color: red;"> <td>❌</td> <td>PC180</td> <td> Uses prettier

Must have https://github.com/pre-commit/mirrors-prettier repo in .pre-commit-config.yaml

</td> </tr> <tr style="color: red;"> <td>❌</td> <td>PC191</td> <td> Ruff show fixes if fixes enabled

If --fix is present, --show-fixes must be too.

</td> </tr> <tr style="color: red;"> <td>❌</td> <td>PC901</td> <td> Custom pre-commit CI message

Should have something like this in .pre-commit-config.yaml:

ci:
  autoupdate_commit_msg: 'chore: update pre-commit hooks'

</td> </tr> </table>

MyPy

<table> <tr><th>?</th><th>Name</th><th>Description</th></tr> <tr style="color: red;"> <td>❌</td> <td>MY101</td> <td> MyPy strict mode

Must have strict in the mypy config. MyPy is best with strict or nearly strict configuration. If you are happy with the strictness of your settings already, ignore this check or set strict = false explicitly.

[tool.mypy]
strict = true

</td> </tr> <tr style="color: red;"> <td>❌</td> <td>MY103</td> <td> MyPy warn unreachable

Must have warn_unreachable = true to pass this check. There are occasionally false positives (often due to platform or Python version static checks), so it's okay to ignore this check. But try it first - it can catch real bugs too.

[tool.mypy]
warn_unreachable = true

</td> </tr> <tr style="color: red;"> <td>❌</td> <td>MY104</td> <td> MyPy enables ignore-without-code

Must have "ignore-without-code" in enable_error_code = [...]. This will force all skips in your project to include the error code, which makes them more readable, and avoids skipping something unintended.

[tool.mypy]
enable_error_code = ["ignore-without-code", "redundant-expr", "truthy-bool"]

</td> </tr> <tr style="color: red;"> <td>❌</td> <td>MY105</td> <td> MyPy enables redundant-expr

Must have "redundant-expr" in enable_error_code = [...]. This helps catch useless lines of code, like checking the same condition twice.

[tool.mypy]
enable_error_code = ["ignore-without-code", "redundant-expr", "truthy-bool"]

</td> </tr> <tr style="color: red;"> <td>❌</td> <td>MY106</td> <td> MyPy enables truthy-bool

Must have "truthy-bool" in enable_error_code = []. This catches mistakes in using a value as truthy if it cannot be falsey.

[tool.mypy]
enable_error_code = ["ignore-without-code", "redundant-expr", "truthy-bool"]

</td> </tr> </table>

Ruff

<table> <tr><th>?</th><th>Name</th><th>Description</th></tr> <tr style="color: red;"> <td>❌</td> <td>RF101</td> <td> Bugbear must be selected

Must select the flake8-bugbear B checks. Recommended:

[tool.ruff]
select = [
  "B",  # flake8-bugbear
]

</td> </tr> </table>

What happened?

MY prototype CRSIndex is broken on the release version: https://github.com/dcherian/crsindex/blob/main/crsindex.ipynb under heading "BROKEN: Successfully align with a copy of itself"

The cell's code is : copy = newds.copy(deep=True) xr.align(copy, newds)

which should always work.

@headtr1ck is https://github.com/pydata/xarray/pull/7140 to blame?

Environment

INSTALLED VERSIONS ------------------ commit: None python: 3.10.6 | packaged by conda-forge | (main, Aug 22 2022, 20:43:44) [Clang 13.0.1 ] python-bits: 64 OS: Darwin OS-release: 21.6.0 machine: x86_64 processor: i386 byteorder: little LC_ALL: None LANG: en_US.UTF-8 LOCALE: ('en_US', 'UTF-8') libhdf5: 1.12.2 libnetcdf: 4.8.1 xarray: 2022.10.0 pandas: 1.5.0 numpy: 1.23.3 scipy: 1.9.1 netCDF4: 1.6.0 pydap: None h5netcdf: 1.0.2 h5py: 3.7.0 Nio: None zarr: 2.13.3 cftime: 1.6.2 nc_time_axis: 1.4.1 PseudoNetCDF: 3.2.2 rasterio: 1.3.2 cfgrib: 0.9.10.2 iris: 3.3.1 bottleneck: 1.3.5 dask: 2022.9.2 distributed: 2022.9.2 matplotlib: 3.6.1 cartopy: 0.21.0 seaborn: 0.12.0 numbagg: 0.2.1 fsspec: 2022.8.2 cupy: None pint: 0.19.2 sparse: 0.13.0 flox: 0.6.0 numpy_groupies: 0.9.19 setuptools: 65.5.0 pip: 22.2.2 conda: None pytest: 7.1.3 IPython: 8.5.0 sphinx: None

memory consumption errors as usual.

@keewis I remember you had an idea for using pip instead of conda?