[Rivet] Histogram normalisation

[Frank Siegert]

Frank Siegert, Tuesday 20 October 2009:
> Andy Buckley, Tuesday 20 October 2009:
> > One further thing, which I'm not sure counts in your "dropped"
> > KFactor proropsal: I don't see how we can automate the finalize steps
> > without always getting ~half of the observables very wrong,
>
> Can you elaborate? Why is it wrong if the finalize for each histogram
> automatically does
>
>   scale(_hist, crossSection()/sumOfWeights())
>
> ?
> The finalize method will then only consist of setting Scale/Norm for
> the histograms where that is necessary, e.g.:
>
>   _hist1->SetScale(1.0/inclusive_xs);
>   _hist2->SetNorm(data_integral);

As an addendum to this: We don't even have to wait for YODA to start this 
transition. Hendrik has improved the make-plots script such that it can 
read a global normalisation setting. So it's already possible to use 
scale(hist, crossSection()/sumOfWeights()) in finalize() together with 
NormalizeToIntegral=1 in *.plot as a replacement of normalize(hist).

I have started to migrate some analyses (in particular the ones where I 
was desperately waiting for the ability to merge runs).

Once we switch more analyses Professor will have to be adapted to make use 
of the normalisations in *.plot in case there are any.

Cheers,
Frank