Fix sign error in expression in GEM digitizer

[watson-ij]

PR description:

A sign error was introduced when turning magic numbers into named parameter in the following commit:
3347619#diff-a4f2f038afa58c34cba02c63dd10a0a5e318afd43c03b05dd941b99c6e00b3a4
The negative sign is used twice, once in the parameter, once in the expression.

@jshlee @yeckang

PR validation:

Checked on a small test. The GEM digi and rechit distributions changed slightly.

Plotting the eff. expression with the correct (i.e. the original expression, and the expression reverted to by this PR) or incorrect signs (i.e. the expression after the changes to add named parameters instead of magic), you can see that the eff. should be lower for the particular branch:

and you can see slightly less gem hits in the cluster size plot for instance:

if this PR is a backport please specify the original PR and why you need to backport that PR:

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• verify that the PR is really intended for the chosen branch
• verify that changes follow CMS Naming, Coding, And Style Rules
• verify that the PR passes the basic test procedure suggested in the CMSSW PR instructions

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-34123/23319

• This PR adds an extra 12KB to repository

[cmsbuild]

A new Pull Request was created by @watson-ij (Ian J. Watson) for master.

It involves the following packages:

SimMuon/GEMDigitizer

@mdhildreth, @cmsbuild, @civanch, @srimanob, @kpedro88 can you please review it and eventually sign? Thanks.
@jshlee, @dildick, @slomeo, @jhgoh this is something you requested to watch as well.
@silviodonato, @dpiparo, @qliphy you are the release manager for this.

cms-bot commands are listed here

[civanch]

please test

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-5752f3/15955/summary.html
COMMIT: e5d4913
CMSSW: CMSSW_12_0_X_2021-06-14-2300/slc7_amd64_gcc900
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week1/cms-sw/cmssw/34123/15955/install.sh to create a dev area with all the needed externals and cmssw changes.

The following merge commits were also included on top of IB + this PR after doing git cms-merge-topic:

• improve precision in jacobianCurvilinearToCartesian #34103 @slava77: improve precision in jacobianCurvilinearToCartesian
• move additional unit tests to python3 #34106 @davidlange6: move additional unit tests to python3

You can see more details here:
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-5752f3/15955/git-recent-commits.json
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-5752f3/15955/git-merge-result

Comparison Summary

Summary:

• No significant changes to the logs found
• Reco comparison results: 369 differences found in the comparisons
• DQMHistoTests: Total files compared: 38
• DQMHistoTests: Total histograms compared: 2862520
• DQMHistoTests: Total failures: 2941
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 2859557
• DQMHistoTests: Total skipped: 22
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 37 files compared)
• Checked 160 log files, 37 edm output root files, 38 DQM output files
• TriggerResults: no differences found

[civanch]

+1

@watson-ij , may be you can add some plot(s) to description?

[watson-ij]

@civanch, yep added a plot showing what the different expressions give for the eff. and how this corresponds to number of gemhits after the update. It looks like theres some minor knock-on effects to the muon parameters in a few of the workflows, and the test picked up some differences from #34103 maybe. I think between those they explain the differences in the plots that are shown in the tests.

[srimanob]

type bug-fix

[srimanob]

+Upgrade

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next master IBs (tests are also fine). This pull request will now be reviewed by the release team before it's merged. @silviodonato, @dpiparo, @qliphy (and backports should be raised in the release meeting by the corresponding L2)

[qliphy]

+1