xarray contrib module

[shoyer]

Over in #1288 @nbren12 wrote:

Overall, I think the xarray community could really benefit from some kind of centralized contrib package which has a low barrier to entry for these kinds of functions.

Yes, I agree that we should explore this. There are a lot of interesting projects building on xarray now but not great ways to discover them.

Are there other open source projects with a good model we should copy here?

• Scikit-Learn has a separate GitHub org/repositories for contrib projects: https://github.com/scikit-learn-contrib.
• TensorFlow has a contrib module within the TensorFlow namespace: tensorflow.contrib

This gives us two different models to consider. The first "separate repository" model might be easier/flexible from a maintenance perspective. Any preferences/thoughts?

There's also some nice overlap with the Pangeo project.

[nbren12]

Thanks for starting this issue @shoyer. One thing I would be interested to know is how sklearn and tensorflow balance code-quality and API consistency with low barrier to entry. For instance, most of the sklearn contrib packages provide classes which inherit from sklearn's Transformer, BaseEstimator, or Regressor classes, which ensures that all the contrib packages share a common interface.

[benbovy]

I like the idea of regrouping contrib projects.

I'd be +1 for the "separate repository" model, which looks indeed easier from a maintenance perspective. However, with this model it might probably be a good thing to also follow some package naming convention (see #1447 for discussion) so that we could easily identify contrib projects in, e.g., import statements or with package managers. I don't have strong opinion on this, though. Maybe it is too restrictive...

... which ensures that all the contrib packages share a common interface.

I'd see xarray contrib packages mainly provide Dataset or DataArray accessors that are too domain-specific to be added as "core" methods.

[benbovy]

Some additional thoughts:

One thing that I like with contrib modules "protected" within the xarray namespace is that it would really help us choosing module names that are short, relevant and ideally the same that the Dataset or DataArray accessors they provide.

However, it is likely that contrib modules may need domain-specific dependencies other than the ones used in xarray "core". With the xarray.contrib model we may end up with a lot of optional dependencies, which may be annoying, e.g., for ci or packaging with conda-forge. To me it would be too restrictive not allowing such specific dependencies in contrib projects.

[shoyer]

I think domain specific dependencies are a pretty decisive argument in favor of the separate repository model.

TensorFlow doesn't relax its code quality standards for contrib packages -- it's more about reducing guarantees of API stability or maintenance. That works OK for TensorFlow in part because the authors of most contrib packages are Google software engineers.

[gajomi]

I don't have any strong opinion about separate repos or contrib submodules, so long as there is some way to improve discoverability of methods.

Having said that, many of the methods mentioned in #1288 are in the numpy namespace, and at least naively applicable to all domains. Would you consider numpy methods with semantics compatible with DataArrays and/or Datasets as appropriate to contribute to core xarray?

[nbren12]

I agree that the separate repository model is probably best. However, should it be in just one repository or in many?

Using many repos would solve the domain-specific dependency problem, but the sklearn-contrib packages are not that discoverable IMO. I found two of them via google on separate occasions before realizing that they were part of the same github organization.

[benbovy]

should it be in just one repository or in many?

One repository for all contrib projects would be hard to maintain if we allow very specific projects, like a little xarray extension to work with the 'xyz' GCM model (which seems to be a common case for extensions). That said, it doesn't prevent us from adding bigger, generic repositories like xarray-scipy.

but the sklearn-contrib packages are not that discoverable IMO.

Hence the suggestion to choose some convention for package naming, e.g., something similar to dask related packages: dask-learn, dask-glm, dask-xgboost, etc.

[benbovy]

To make methods even more discoverable, we might also add the x prefix to DataArray or Dataset accessors. This would work quite well with auto-completion, even though x alone is very often used as coordinate. Like suggested in #1447, we could have something like

$ conda install xarray-scipy -c conda-forge`

>>> import xarray as xr
>>> import xscipy

>>> da = xr.DataArray(...)
>>> da.xscipy.method()

But maybe that's too much x...

[jhamman]

My 2-cents. I think we could consider setting up an xarray-contrib organization. I don't see how a xr.contrib namespace buys us all that much, except for some additional book-keeping in the core xarray package. My thought would be to let individual projects decide 1) if they want to reside inside the xarray-contrib organization, and 2) whether or not to use the accessor api available in xarray now. We could easily add a page to the xarray docs that points to a collection of projects.

Side note, we don't have to use it but I did grab the xarray-contrib organization name just in case.

[max-sixty]

Re the comment from @benbovy

Even before this, let's put a list of projects that are closely integrated with xarray somewhere?

[nbren12]

@maxim-lian There is a very short list of such packages hidden in the xarray documention.

In general, there are a ton of these awesome-... repos floating around the internet which just list the useful/related tools/libraries which are related to ... . For example, there are repos out there like awesome-python and awesome-bash. Maybe someone could start an awesome-xarray package.

[shoyer]

Personally I'd rather have "awesome xarray" listed somewhere prominently in the xarray docs, along with mentions inline in the docs anywhere where they are particularly relevant . The very short list that is currently there is based upon a handful of projects that I knew about a few years ago, but it's definitely woefully out of date now.

…

On Fri, Feb 23, 2018 at 9:23 PM Noah D Brenowitz ***@***.***> wrote: @maxim-lian <https://github.com/maxim-lian> There is a very short list of such packages hidden in the xarray documention <http://xarray.pydata.org/en/stable/internals.html?highlight=xgcm#extending-xarray> . In general, there are a ton of these awesome-... repos floating around the internet which just list the useful/related tools/libraries which are related to ... . For example, there are repos out there like awesome-python <https://github.com/vinta/awesome-python> and awesome-bash. Maybe someone could start an awesome-xarray package. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#1850 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ABKS1oUunEGU95WyDsCgTYpuXKdybftIks5tX5y4gaJpZM4RoiXN> .