[Rivet] a few issues/problems with Rivet and its tools

[Andy Buckley]

On 26/01/15 15:03, roman lysak wrote:
> 
>  Dear Rivet authors,
> 
> in preparing the Rivet routine for the upcoming 13 TeV ATLAS min-bias
> analysis, we encountered the following problems with Rivet tools:
> 
> - concerning 'Histo2D' objects:
>     - Rivet::Analysis::scale() --> seems it does not work (is not
> implemented) for Histo2D
>     - yoda2root does not work for Histo2D: it seems 'yoda.to_root' is
> where it fails

Yes, 2D histograms are not fully implemented at present. The next
version of YODA should add overflows for 2D histos and fix 2D I/O, at
which point we can start supporting them properly. I'll make sure that
we provide an Analysis::scale() function for them at the same time.

> - concerning Profile1D:
>    - yoda2root does not work: after conversion it seems that all bins
> are zeros ( checking with TProfile::GetBinContent() and GetBinEntries() ).

This is a place where we could really benefit from external assistance!
Note the comment at L166 of ROOTCnv.h:

https://yoda.hepforge.org/hg/yoda/file/68319e860944/include/YODA/ROOTCnv.h#l166

"This part is probably wrong -- also need to do something with GetW,
GetW2, GetB, GetB2, and/or GetBinSumw2? ROOT docs are 100% useless..."

;-)

I just took another look at the ROOT documentation and still can't see
how to set the mean values and errors on a ROOT TProfile. Should I just
use SetBinContent and SetBinError with the bin.mean() and bin.stdErr()
values respectively? The TProfile documentation gives the impression
that it can implement several error options, but would need <y^2> and
<y> running sums in each bin to do it, and I can't see where those are
being stored/exposed.

If just calling SetBinContent + SetBinError would be sufficient (and
would work), please let me know... it's an easy change to make!

Cheers,
Andy

-- 
Dr Andy Buckley, Royal Society University Research Fellow
Particle Physics Expt Group, University of Glasgow / PH Dept, CERN