[Rivet] root usage in rivet

[Andy Buckley]

Altan Cakir wrote:
> Hi Andy,
> 
> i need to asked one more question related to usage ROOT histograms via
> Rivet framework. Actually it is not clear wiki page how to do it .
> Therefore, i need a little bit clearfy in my mind. For example, in order
> to generate events with Sherpa , shoudl i use sherpa data card(s) or
> some another declaration.

That depends on your needs. If you have a static Sherpa configuration
that you wish to use, then either using Sherpa's native conf files, or a
rivetgun param file is probably best. If you're doing parameter scans,
then you can use the rivetgun "-p <key>=<val>" arguments to override
particular parameters without having to write anything to file.

> IN addition to that , I saw one script in
> order to convert Aida file to Root file but it is not clear. I think the
> best way how can i add my root program in AFS to rivet.

I've never used it, but Lars may be able to help. Note that Rivet
currently writes all histograms out as the same AIDA "DataPointSet"
type, since most reference histograms are either normalised or profile
histos, hence the aida2root converter (or the ROOT output format from
rivetgun) will only produce TGraph objects with no data about the events
used to fill them. This isn't ideal, and the next version of Rivet will
use a much richer histogramming interface and format.

If you want to use ROOT tuples from inside a Rivet routine, then the
ExampleTree analysis may be a useful template. Such routines aren't very
useful for increasing the analyses in Rivet, though, so we don't make
encourage such an approach. Are you wanting to get ROOT plots from
existing Rivet analyses or to write a new analysis?

> If i am able to
> succeed properly in all case , i can prepare one basic wiki page to
> clearify the people like me :)

That would be very helpful!

Best wishes,
Andy