switch CCC on in Conversion Pattern recognition

[VinInn]

switch CCC on in Conversion Pattern recognition
For consistency with all other steps including Conversion Seeding itself.
At 50ns (Run2012C) the number of conversion candidates increases.
the regression becomes very small at electron/photon level

It was kept out of #5853 to disentangle technical changes from behavior modification

[cmsbuild]

A new Pull Request was created by @VinInn (Vincenzo Innocente) for CMSSW_7_4_X.

switch CCC on in Conversion Pattern recognition

It involves the following packages:

RecoTracker/ConversionSeedGenerators

@cmsbuild, @nclopezo, @StoyanStoynev, @slava77 can you please review it and eventually sign? Thanks.
@ghellwig, @makortel, @GiacomoSguazzoni, @rovere, @VinInn, @appeltel, @gpetruc, @cerati, @dgulhan, @venturia 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.
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[cmsbuild]

+1
Tested at: bb899ce
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-6760/1405/summary.html

[slava77]

... testing

[slava77]

+1

for #6760 bb899ce
tested in CMSSW_7_4_X_2014-12-02-1400 (test area sign471)
The changes are as expected. Other than fairly small changes in convTrackCandidates and even smaller in allConversions, changes are pretty nonexistent.

Here is a summary of our tests:

• timing, based on wflow 25202: about 10% decrease in convTrackCandidates CPU (0.15% of RECO)
• visible increase in the number of conversionStepTracks and allConversions
• very very small change in the PFCandidates

More details on conversionStepTracks and allConversions
In 1313 (dijet high-pt)
most of the increase is in 6 and 5-hit tracks

The amount of changes in conversionStepTracks is smaller in less dense events

• most in 3 TeV dijet (+~5%)
• pretty small in minbias (~<1%)
• small in Photon2012B (few % up)
• a few % up in 25ns ttbar PU35. Here the increase is most visible in the barrel-endcap overlap region
• no changes in higher stat ele or photon gun events

[VinInn]

ping

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_4_X IBs unless changes (tests are also fine). This pull request will be automatically merged.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-6760/1405/summary.html