Parallelize isotropize

[roxyboy]

I implemented @shoyer 's amazing numpy_groupies hack to parallelize the isotropization of spectra. This addresses issues #9 and #87 .

[rabernat]

This is cool Takaya! We could also potentially use this in xhistogram

I will review this after the Thanksgiving holiday.

[rabernat]

p.s. Isn't this going into xarray itself? Is it necessary to put it in xrft?

[roxyboy]

p.s. Isn't this going into xarray itself? Is it necessary to put it in xrft?

I think it eventually is going to but I checked the xarray issue log and it seems that there's still some issues for it to be implemented upstream. So I figured I'd just add it to xrft in the mean time.

[roxyboy]

@rabernat Do you think we should keep this PR out until numpy_groupies gets implemented more upstream?

[rabernat]

This looks great! Do we have tests for this feature already? If so, I approve.

[roxyboy]

This looks great! Do we have tests for this feature already? If so, I approve.

The test_isotropize tests isotropization for both chunked and non-chunked data so I think the pre-existing tests cover this feature. But I'll add a bit more to the test that checks the slopes.