Reintegrate parallel crossvalidation

[lkuchenb]

Would be great to see this back in develop

[vigsterkr]

@lkuchenb cool! let's see what CI says about this :)

[karlnapf]

so travis didnt complain more than the current broken things
@vigsterkr iirc the bugs in the parallel xvalidation with clone were caused by parallel issues that were fixed?

[vigsterkr]

@karlnapf i think it was completely other stuff :) only thing we need to test that i vividly remember that for some in one of the ipython notebooks the CV stuff was failing with this .... so somebody should try to run the notebook using this patch (imo there's a CV notebook, or?)

[vigsterkr]

@lkuchenb i'll try to finish up the input parser story in cpp11 branch so we can merge and then we can rebase this one to be sure about the MSVC et.al.

[karlnapf]

There is one
@lkuchenb wanna have a go at that?

[vigsterkr]

wooohooo, getting a parallel CV, how awesome is this in 2017! 💃

[karlnapf]

Next step -- don't clone the fucking data. This is madness in 2017 !!!