Major JME developments for 73x

[rappoccio]

This PR contains a large number of JME developments for 73x :

1. Updates to use new fastjet 3.1.0 (Moving fastjet threading PR to cms/v3.1.0 cms-externals/fastjet#8)
2. Updates to new API for n-subjettiness for fastjet-contrib 1.014 (Adding fastjet contrib version v1.014, also changes for thread safety cms-externals/fastjet-contrib#2)
3. Added changes to PUPPI from the code review here (Puppi #5500)
4. Added several new tools, none of which are to be executed in RECO until further notice :
   • Constituent subtraction
   • SoftKiller
   • SoftDrop
   • PUPPI

Two notes :

• There is a new package, CommonTools/PileupModules. It would aid development to have these separate from CommonTools/ParticleFlow (which is focused on the "top projection" code).
• The current output is set up as an intermediate stage where PFCandidates are produced along with a valueMap of four vectors. This is a stand-in until I make a migration to the ThinnedCollection, but this is better treated together rather than piecemeal.

Also adding @violatingcp and @nhanvtran to watch this.

Final note : This seems to be stuck "Checking mergeability...". I have updated to CMSSW_7_3_X_2014-11-07-0200 and it merges fine, so I presume this is a github issue.

[cmsbuild]

A new Pull Request was created by @rappoccio for CMSSW_7_3_X.

Major JME developments for 73x

It involves the following packages:

CommonTools/PileupModules
DataFormats/Math
RecoJets/Configuration
RecoJets/JetAlgorithms
RecoJets/JetProducers

The following packages do not have a category, yet:

CommonTools/PileupModules

@cmsbuild, @nclopezo, @StoyanStoynev, @slava77 can you please review it and eventually sign? Thanks.
@yslai, @nhanvtran, @mariadalfonso, @TaiSakuma, @schoef 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.
@nclopezo, @ktf you are the release manager for this.
You can merge this pull request by typing 'merge' in the first line of your comment.

[slava77]

Hi Sal,

Please add a summary of physics and technical performance changes from this PR,
(a link to a PUPPI talk, how much faster the fastjet is I recall you mentioned it's faster etc)

[rappoccio]

On 1000 events, some speed improvements for fastjet 3.1.0 are :
AK4 : 0.018 --> 0.014 s/event
AK8 : 0.039 --> 0.018 s/event
CA8 : 0.051 --> 0.021 s/event

So, reductions of 0.2-2.0 are observed depending on the cone size.

The algorithms have been studied in
http://cms-physics.web.cern.ch/cms-physics/public/JME-14-001-pas.pdf
http://cms-physics.web.cern.ch/cms-physics/public/JME-14-002-pas.pdf
http://arxiv.org/abs/1410.4227
http://arxiv.org/abs/arXiv:1407.6013

We haven't decided exactly which to implement, but overall similar pileup mitigation performances have been observed from PUPPI, constituent subtraction, and soft killer, in particularly in conjunction with any grooming technique. PUPPI seems to have the most benefits in one package, though, so that's most likely the way forward.

[slava77]

Which IB has the new version of the fastjet?
On Nov 7, 2014 6:57 PM, "rappoccio" notifications@github.com wrote:

On 1000 events, some speed improvements for fastjet 3.1.0 are :
AK4 : 0.018 --> 0.014 s/event
AK8 : 0.039 --> 0.018 s/event
CA8 : 0.051 --> 0.021 s/event

So, reductions of 0.2-2.0 are observed depending on the cone size.

The algorithms have been studied in
http://cms-physics.web.cern.ch/cms-physics/public/JME-14-001-pas.pdf
http://cms-physics.web.cern.ch/cms-physics/public/JME-14-002-pas.pdf
http://arxiv.org/abs/1410.4227
http://arxiv.org/abs/arXiv:1407.6013

We haven't decided exactly which to implement, but overall similar pileup
mitigation performances have been observed from PUPPI, constituent
subtraction, and soft killer, in particularly in conjunction with any
grooming technique. PUPPI seems to have the most benefits in one package,
though, so that's most likely the way forward.

—
Reply to this email directly or view it on GitHub
#6273 (comment).

[rappoccio]

None yet, still waiting on @Dr15Jones and @ktf for integration of both externals.

[slava77]

uhm, ok.
I guess there's no way to test it yet either (or is there a scram tool command to pickup the externals?)
Looks like a preemptive PR that'd make cmsbuild violently happy.

[rappoccio]

We are indeed on hold, this was just to get things moving. As far as I can tell with the tests I got from Chris, we should be good to go with the fastjet integration.

[slava77]

So, the compilation error due to missing SoftKiller is due to fastjet-contrib

I see it's in https://fastjet.hepforge.org/contrib/contents/1.014.html
and it's the first time it appears in fastjet-contrib
our current version is 1.009-cms3 in main 73X => 1.009-cms5 in DEVEL.
https://github.com/cms-externals/fastjet-contrib has 1.014 already.

[rappoccio]

@slava77 : correct, I mentioned the fastjet-contrib requirement above.

I can also do the rebase. Grrr. Give me a little while.

[rappoccio]

I cannot get this branch to rebase correctly. Thus I will close this PR and open a new one.