replace unsupported `get` keyword with `scheduler`

[orbeckst]

Expected behaviour

No warnings are raised when using dask.

PMDA should work with latest dask releases ≥ 0.18.0

Actual behaviour

Using the get= kwarg is deprecated removed (raises TypeError), instead use scheduler=

pmda/test/test_contacts.py::TestContacts::()::test_startframe
  /home/travis/miniconda/envs/test/lib/python3.6/site-packages/dask/base.py:835: UserWarning: The get= keyword has been deprecated. Please use the scheduler= keyword instead with the name of the desired scheduler like 'threads' or 'processes'
    warnings.warn("The get= keyword has been deprecated. "

This is now a TypeError.

Code to reproduce the behaviour

• warning: see https://travis-ci.org/MDAnalysis/pmda/jobs/397005019
• exception: see PR Add InterRDF_s #70

Currently version of MDAnalysis:

(run python -c "import MDAnalysis as mda; print(mda.__version__)")
(run python -c "import pmda; print(pmda.__version__)")
(run python -c "import dask; print(dask.__version__)")

[kain88-de]

I think for a longer period we should support both keywords. This allows people to use also an older dask version and not break scripts with another release.

[orbeckst]

Good idea!

…

-- Oliver Beckstein email: orbeckst@gmail.com

Am Jun 26, 2018 um 13:17 schrieb Max Linke ***@***.***>: I think for a longer period we should support both keywords. This allows people to use also an older dask version and not break scripts with another release. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub, or mute the thread.

[VOD555]

It seems in the new version of dask (0.20.0) released on 10/26/2018, it raises an error on the use of the get= keyword and set_options (http://docs.dask.org/en/latest/changelog.html).

[orbeckst]

I think for a longer period we should support both keywords. This allows people to use also an older dask version and not break scripts with another release.

Would be nice to support old and new dask, but dask is moving so quickly, I don't think we have the developer time to do this. Instead we will have to require dask ≥ 0.18.0 and have users update. At least that is relatively painless for dask.

[kain88-de]

I'm also OK saying this library is cutting edge. We explicitly claim the library is not stable in the readme.