New HeavyIon ClusterCompatibility object and producer for beam scraping removal

[appeltel]

This request is to create a new "ClusterCompatibility" DataFormat and associated producer for use in the HeavyIon reconstruction scenario.

This DataFormat is required in order to facilitate a change in analysis strategy for heavy ion data in 2015, where RECO may be replaced with AOD. In previous years, RECO event content has been stored which includes pixel clusters. The pixel cluster information was used to run the HLTPixelClusterShapeFilter to remove beam scraping events from analysis samples. The ClusterCompatibility object provides a small (2.5 kB compressed) summary of the cluster-vertex compatibility information given a hypothesis of a collision vertex at several positions along the z-axis.

From the information stored in the ClusterCompatibility object, it is possible to implement a filter with identical behavior to the HLTPixelClusterShapeFilter that does not need access to the collection of pixel clusters, which is not present in AOD. Such a filter has been implemented and tested, but is not part of this pull request.

In addition to allowing the removal of beam scraping events from analysis samples, the ClusterCompatibility object could be used to identify PbPb collision events with multiple collision vertices. This is not currently possible using tracks, as the specialized heavy ion tracking is performed relative to a specific single vertex position.

[cmsbuild]

A new Pull Request was created by @appeltel (Eric Appelt) for CMSSW_7_5_X.

New HeavyIon ClusterCompatibility object and producer for beam scraping removal

It involves the following packages:

DataFormats/HeavyIonEvent
RecoHI/Configuration
RecoHI/HiCentralityAlgos

@cmsbuild, @cvuosalo, @nclopezo, @slava77 can you please review it and eventually sign? Thanks.
@azsigmon, @yslai, @MiheeJo, @jazzitup, @richard-cms, @echapon, @yenjie, @kurtejung, @mandrenguyen, @dgulhan, @yetkinyilmaz this is something you requested to watch as well.
You can sign-off by replying to this message having '+1' in the first line of your reply.
You can reject by replying to this message having '-1' in the first line of your reply.
If you are a L2 or a release manager you can ask for tests by saying 'please test' in the first line of a comment.
@nclopezo you are the release manager for this.
You can merge this pull request by typing 'merge' in the first line of your comment.

[slava77]

@cmsbuild please test

[cmsbuild]

The tests are being triggered in jenkins.

[cmsbuild]

+1
Tested at: 10dcd67
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-8996/4568/summary.html

[slava77]

+1

for #8996 94eda2a

• additionally tested in CMSSW_7_5_0_pre4 /test area sign547/ with 100 event run of 140.53 wflow:
  • hiClusterCompatibility shows up both in RECO and AOD event contents and takes 2409 bytes/event (0.24% of the current AOD event size)
  • hiClusterCompatibility module takes 100 ms/event, which is 0.14% of RECO processing time
  • all of the CPU and disk size bloat is from the 400 times loop over hits in ClusterCompatibilityProducer::getContainedHits method. I suggest this is checked and reduced.

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_5_X IBs unless changes (tests are also fine). This pull request requires discussion in the ORP meeting before it's merged. @davidlange6, @nclopezo, @smuzaffar

[davidlange6]

+1