temporary fix to avoid iter7 tracks being discarded

[arizzi]

fix to avoid losing tracks that are now recoed as iter7 (jetmet validation reported issue in charged hadron fractions).
This is temporary as PF people are working on simply removing the cuts on iteration number

[cmsbuild]

A new Pull Request was created by @arizzi for CMSSW_7_2_X.

temporary fix to avoid iter7 tracks being discarded

It involves the following packages:

RecoParticleFlow/PFProducer

@nclopezo, @cmsbuild, @Degano, @StoyanStoynev, @slava77 can you please review it and eventually sign? Thanks.
@bachtis, @lgray 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.

[slava77]

Hi Andrea,

Could you post some more details about the reported problem and the effect of the change at the moment.

Thanks

[arizzi]

here the mail from matthias and viola

Dear Andrea and Giuseppe,

We contact you, since we observe JetMET validation of release 7_2_0_pre1 a
feature both for data and MC, which we think could be related to your pull
request of #4162

a short summary of the feature is:
In 7_2_0_pre1 the charged multiplicity of jets goes down, charged fractions
for PFJets (default, no chargedHadron subtraction is applied) and PFMet
decrease, neutral and photon fractions increase. We observe it both for MC
and data. On data we have the information in pt-bins and we observe that it
only appears for high pt jets over 100 GeV, anything else seems to be in
perfect agreement with respect to the composition. At 100 GeV we see a
clear sharp drop of the order of 6 % over a 40 GeV range of the charged
hadronic fraction, before we saw a trend to slightly lower charged hadronic
fractions but still a pretty stable behavior between 50-500.

We checked now the release notes
https://github.com/cms-sw/cmssw/releases/CMSSW_7_2_0_pre1 and we think that
maybe the pull request #4162 could lead
to those features we observe. Do you think this can be the case, and if
yes, is what we observe kind of expected by you and desired.

More details follow now:

For CaloJets and CaloMET everything agrees with the baseline release of
7_1_0. For PFMet and PFJets many quantities, especially physics quantities
like pt,eta,phi etc agree. We observe a certain feature though for the
composition.

The ChargedHadronEtFraction for PFMET is shited to lower values, the
neutral fraction consequently to higher values (7_2_0_pre1 is in black, in
blue the baseline of the previous release)

https://cms-pdmv.cern.ch/ReleaseMonitoring/CMSSW_7_2_0_pre1VSCMSSW_7_1_0/FullSimReport/RelValQCD_FlatPt_15_3000HS_13_POSTLS172_V1/f43ca3a069.html

the neutral fraction in data is attached in a png (Data_PFMET_neutral...).
Here the release 7_2_0_pre1 is in blue. Clearly the distribution has a
longer spread and a higher mean.

When we looked at jets we spread the information out in pt bins. It seems
the change only happens though at high pt jets (see attached plot for
ChargedHadronFraction (Data_PFJets_CHFrac...) at high Pt, in blue
7_2_0_pre1). Since we realized that the statistics of the centrally
produced plots is largely different, we wanted to make sure that this might
not be an artefact of different pileup distributions (different run periods
had different conditions, and we know vastly different pile up conditions
can affect the internal structure of jets and MET). So we reran everything
privately, and we can safely exclude that (see CHFrac_highPt_Barrel...).
This time we have over 360 k jets vs 390 k jets in the histogram, so it is
roughly the same amount and for sure it is statistically significant).

The pt dependence can be seen for the high stat rerun in PFJets_CHFracVspT
plot (see
https://cmsweb.cern.ch/dqm/relval/plotfairy/overlay?obj=archive%2F199812%2FJetHT%2FCMSSW_7_1_0-GR_R_71_V6_RelVal_jet2012C-v1%2FDQM%2FJetMET%2FJet%2FUncleanedak4PFJets%2FCHFracVSpT_EndCap;obj=archive%2F199812%2FJetHT%2FCMSSW_7_2_0_pre1-GR_R_72_V1_RelVal_jet2012C-v1%2FDQMIO%2FJetMET%2FJet%2FUncleanedak4PFJets%2FCHFracVSpT_EndCap;w=600;h=600;ref=ratiooverlay
for the endcap)

see
https://cmsweb.cern.ch/dqm/relval/plotfairy/overlay?obj=archive%2F199812%2FJetHT%2FCMSSW_7_1_0-GR_R_71_V6_RelVal_jet2012C-v1%2FDQM%2FJetMET%2FJet%2FUncleanedak4PFJets%2FChMultiplicity_highPt_EndCap;obj=archive%2F199812%2FJetHT%2FCMSSW_7_2_0_pre1-GR_R_72_V1_RelVal_jet2012C-v1%2FDQMIO%2FJetMET%2FJet%2FUncleanedak4PFJets%2FChMultiplicity_highPt_EndCap;w=600;h=600;ref=ratiooverlay
for the multiplicity, which are also shifted to lower values.

Best Regards,
Matthias & Viola

On Tue, Jul 15, 2014 at 11:45 PM, Slava Krutelyov notifications@github.com
wrote:

Hi Andrea,

Could you post some more details about the reported problem and the effect
of the change at the moment.

Thanks

—
Reply to this email directly or view it on GitHub
#4662 (comment).

[cmsbuild]

+1
Tested at: 62237a7
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-4662/347/summary.html

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-4662/347/summary.html

[StoyanStoynev]

I am checking the performance.

[StoyanStoynev]

Just the results for now - please confirm the observations are acceptable.
I tested 62237a7 on top of CMSSW_7_2_X_2014-07-16-0200. Short and extended matrix tests, fwlite and DQM script based tests.
I can see the features described above now in the opposite direction (so the "fix" works). I do see that indeed (PF) quantities are affected mostly at high pt though there are exceptions. I show here wf 38 (QCD) as most features are seen there best, I'll note explicitly another wf if shown. Red is this PR.

(although no title to suggest the variable plotted it is vs pt)

Fractions/multiplicities also go in the right direction:

In addition I see effects on isolation, and tau reco:

I also see some effects on other objects:
(this one plot is wf16 - 1TeV electrons)

In fact differences are seen in wf 38, 202 (ttbar) and 16. I understand these are all fine.

[StoyanStoynev]

I think only the muon part (isolation in particular) is raising some concerns for me, just because of the magnitude of the change.

[StoyanStoynev]

@arizzi - ping.
@bachtis I'd appreciate your comments too.

[arizzi]

ping what? I see no question asked (btw I'm on vacation and this should be handled by PF people). Anyhow the comparison with pre1 that is somehow buggy because of iter7 tracks being ignored makes little sense to me.

[StoyanStoynev]

ping comment ("please confirm the observations are acceptable"). There are performance changes introduced which by default are unwanted and if they are, people requesting them should agree they are "as expected"; it was claimed it was a temporary
fix and thus may have unwanted consequences (and iter7 making or not sense in PF is something to comment on indeed). Have a nice vacation.

[arizzi]

@bachtis can you confirm it is ok with you?
I do not see anything particularly strange in the plots above

[webermat]

based on the charged multiplicity plot and charged hadron fraction move in the direction we want (i.e. to where they were in release 7_1_0. Judging by the available statistics it also seems to be the around the desired magnitude.

[StoyanStoynev]

+1
Based on the review above and the significant time that was available for comments.

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_2_X IBs unless changes (tests are also fine).