[Rivet] converting 2D histogram from ROOT to AIDA file

[Roman Lysak]

  Hi Andy,


On 10/22/2012 06:53 PM, Andy Buckley wrote:
> Hi Roman,
>
> I'm not sure that Rivet currently supports "autobooking" of analysis
> histograms from 2D histos -- we've not yet had an analysis in which a 2D
> histo was the main physics result (and would be possible with a single
> MC run.) There are also obvious problems with plotting data/MC
> comparisons on 2D plots! For that reason, compare-histos knows nothing
> about them. I don't think HepData knows anything about how to handle 2D
> histograms either, which will presumably be a bit of an issue for this
> analysis when it comes to submitting the data.
>
> So to convert a ROOT file of 2D histograms to AIDA you could write a
> PyROOT script to dump out the appropriate XML -- this is pretty
> straightforward.
sure, it can be done, I was just hoping someone already did this before :)

>   But I'm not sure how much can usefully be done with the
> result. Are the 2D histos absolutely essential? They couldn't be reduced
> to e.g. a bunch of 1D slices which can actually be used for visually
> straightforward comparison?
The analysis I'm referring to is public:

http://inspirehep.net/record/1093734/

I'm talking about Fig.2 where the full information about 
forward-backward correlation is preserved.
Of course, the 2D plot can be converted into 1D histograms.
Actually, part of the information (diagonal, probably the most 
important) is also contained in Fig 3a.

Thanks for help,
   Roman



>
> I appreciate this is maybe an unpublished analysis that you're talking
> about, and hence can't be shown on this open list, but if not can you
> point us at it so we can see the problem data? :-)
>
> Patches to improve Rivet are also very welcome! But note that the
> histogramming is already being overhauled -- if you want to help out,
> get in touch and we'll point you at the development version so you can
> improve the 2D histogramming there.
>
> Andy
>
>
> On 19/10/12 10:32, Roman Lysak wrote:
>>    Dear Rivet authors,
>>
>> I'm working on Rivet implementation of an analysis which creates 2D
>> histogram and need to convert data histograms from .root to .aida file.
>> I know one can convert 1D histograms (of graphs) from ROOT file into
>> AIDA file by combination of 'root2flat' and 'flat2aida'.
>> As far as I understand, root2flat is not working for 2D histograms.
>> Do you know about some other tools (even unofficial) which would be able
>> to do such conversion for 2D histograms?
>>
>> Thanks a lot,
>>    Roman
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>