BTagPerformance.h: added cmath header to fix the header consistency error

[smuzaffar]

This adds the missing header cmath for https://github.com/cms-sw/cmssw/blob/master/PhysicsTools/PatExamples/interface/BTagPerformance.h which uses sqrt without including cmath header. This causes header consistency error [a]

[a] https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-d1f908/48627/headers_chks.log

>> Compiling src/RecoBTag/SecondaryVertex/interface/CandidateBoostedDoubleSecondaryVertexComputer.h 
src/PhysicsTools/PatExamples/interface/BTagPerformance.h: In member function 'void BTagPerformance::Eval()':
src/PhysicsTools/PatExamples/interface/BTagPerformance.h:73:20: error: 'sqrt' was not declared in this scope
   73 |       double err = sqrt(eff * (1 - eff) / b_all);
      |                    ^~~~
src/PhysicsTools/PatExamples/interface/BTagPerformance.h:87:20: error: 'sqrt' was not declared in this scope
   87 |       double err = sqrt(eff * (1 - eff) / c_all);
      |                    ^~~~
src/PhysicsTools/PatExamples/interface/BTagPerformance.h:101:20: error: 'sqrt' was not declared in this scope
  101 |       double err = sqrt(eff * (1 - eff) / udsg_all);

[smuzaffar]

please test

[cmsbuild]

cms-bot internal usage

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-49146/46431

• There are other open Pull requests which might conflict with changes you have proposed:
  • File PhysicsTools/PatExamples/interface/BTagPerformance.h modified in PR(s): Drop not used Vector3D in header and Update BTagPerformance.h #49104

[cmsbuild]

A new Pull Request was created by @smuzaffar for master.

It involves the following packages:

• PhysicsTools/PatExamples (analysis)

@tvami can you please review it and eventually sign? Thanks.
@AlexDeMoor, @Ming-Yan, @Senphy, @andrzejnovak, @castaned, @pavlo-kashko, @philippgadow this is something you requested to watch as well.
@ftenchini, @mandrenguyen, @sextonkennedy you are the release manager for this.

cms-bot commands are listed here

[cmsbuild]

+1

Size: This PR adds an extra 20KB to repository
Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-506ad0/48637/summary.html
COMMIT: c17689a
CMSSW: CMSSW_16_0_X_2025-10-13-1100/el8_amd64_gcc13
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week1/cms-sw/cmssw/49146/48637/install.sh to create a dev area with all the needed externals and cmssw changes.

Comparison Summary

Summary:

• You potentially added 1 lines to the logs
• Reco comparison results: 6 differences found in the comparisons
• DQMHistoTests: Total files compared: 51
• DQMHistoTests: Total histograms compared: 3940073
• DQMHistoTests: Total failures: 58
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3939995
• DQMHistoTests: Total skipped: 20
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 50 files compared)
• Checked 218 log files, 188 edm output root files, 51 DQM output files
• TriggerResults: no differences found

[cmsbuild]

REMINDER @mandrenguyen, @ftenchini, @sextonkennedy: This PR was tested with #49159, please check if they should be merged together

[iarspider]

The PRs are independent.

[tvami]

+1

[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. @sextonkennedy, @mandrenguyen, @ftenchini (and backports should be raised in the release meeting by the corresponding L2)

[ftenchini]

+1