sPHENIX tracking discussion

[Christof Roland <christof.roland AT cern.ch>]

Hi Tony,

I think we should at least make the particle selection for which we want truth clusters 

configurable with corresponding getters and setters.

i just realized that the truth clusters I need to be matched to reco clusters are not the 

same as created in the truth clustering module. 

I need the ones that are created in the SvtxTruthEval class. Are the algorithms 

to create those still comparable?

Another question I had is the treatment of out of time pileup clusters. At which point 

do I get the true position of the g4hits in there own time frame and how do I get the 

actualy observer positions in the time frame of the signal event (gt==0 i guess)

Cheers

   Christof 

On 21. Jun 2021, at 20:50, Anthony Frawley via sPHENIX-tracking-l <sphenix-tracking-l AT lists.bnl.gov> wrote:

Hi All,

I am following up on the question in the meeting this morning about how the truth clustering is done.

The code that fills the truth cluster asks for all g4particles from the truth info container like so: 

   PHG4TruthInfoContainer* truthinfo = findNode::getClass<PHG4TruthInfoContainer>(topNode, "G4TruthInfo"); 

   PHG4TruthInfoContainer::ConstRange range = truthinfo->GetParticleRange();

and loops over all of the g4particles. It sums the energy in each layer from the g4hits for that particle, and fills a multimap of (layer, truth_cluster).

However it does have a check for whether the scan_for_embedded flag is set, and it skips clusters from all particles for which gembed <= 0.

So if you run with scan_for_embedded set to true, you get truth clusters only from embedded particles. 

Should we change that?

Tony

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