Using circmean to get circular mean

[steob92]

Resolves #213

Using scipy.stats.circmean to get the circular mean when getting the average RA.

[tobiaskleiner]

Thanks @steob92! The scipy implementation now adds the phase shift res[res < 0] += 2*pi. (Previous negative values are also working with gammapy/astropy.) You can merge.

[GernotMaier]

@steob92 , @tobiaskleiner - does this require a re-processing? How significant is the change? Does it justify a new release of V2DL3?

[tobiaskleiner]

@GernotMaier @steob92 not sure it is needed. There is no effect on the coordinate, the calculation was the same implementation as in scipy except for the phase shift (i.e. Ra coordinate Ra=-150 --> Ra=210). Maybe we can wait for another major release (if happening) otherwise we reprocess in a few months?

[GernotMaier]

running v2dl3 takes a day, so it is not a computing issue. I just need to know.

[steob92]

@GernotMaier I originally started looking into this because when querying a large datastore, I wouldn't find the correct number of runs.

When using the high level interface (config + Analysis, for example: https://docs.gammapy.org/1.2/tutorials/analysis-2d/ring_background.html). The coordinates passed to the obs_cone will be used to query the observation table which will use RA/DEC_PNT. See:
https://docs.gammapy.org/1.2/_modules/gammapy/data/obs_table.html#ObservationTable.select_observations

With the current pre-processed files, one needs to generate a runlist for a region of interest using VLISTBUILDER. I think VLISTBUILDER is still semi offline. We lost the ability to automatically update it, I'm also not sure if it was updated with runs beyond 2018...

I think it's worth reprocessing... This fix would remove the need for VLISTBUILDER when running a gammapy analysis. But I'm also not the one who will have to babysit the scripts!

[GernotMaier]

@steob92 - could you release a new version? 0.6.0?

[steob92]

Sure, are the automatically generated release notes okay, or would you like a comment about circmean? I also see some VEGAS changes by @matthew-w-lundy and @deividribeiro.