MTD geometry: update pixel index definition from RectangularMTDTopology

[fabiocos]

PR description:

This PR proposes a solution to the issue #43942 , or at least to the MTD-related part of it. The recent update of ETL digitization in #43762 utilizes also hits outside the active part of the pixel area, and therefore needs the computation of pixel indices also for points very close to the geometrical border of the volume. Due to numerical accuracy, they can exceed the maximum allowed value, producing a chain of problems in the downstream code.

This PR introduces a pixelIndex method in RectangularMTDTopology to correctly compute the indices based on the position in the module, introducing a safety check for border situations. The geometry test is instrumented to possibly catch problems, and this new method is used in the rest of the MTD code where applicable.

PR validation:

The code appears to solve the reproducible crash in recent ASAN builds within the MTD clustering algorithm, and allows the unit test of Geometry/MTDGeometryBuilder to pass smoothly.

[cmsbuild]

cms-bot internal usage

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-44051/38992

• This PR adds an extra 32KB to repository

• There are other open Pull requests which might conflict with changes you have proposed:

  • File Geometry/MTDGeometryBuilder/src/MTDGeomUtil.cc modified in PR(s): [MTD simulation, validation]: implementation of MTD clusters association maps #43913
  • File SimFastTiming/FastTimingCommon/src/ETLDeviceSim.cc modified in PR(s): Temporarily revert "A new digitization model for the ETL detector" #44031

[cmsbuild]

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

It involves the following packages:

• Geometry/MTDGeometryBuilder (upgrade, geometry)
• SimFastTiming/FastTimingCommon (upgrade, simulation)

@bsunanda, @mdhildreth, @cmsbuild, @Dr15Jones, @subirsarkar, @civanch, @makortel, @srimanob can you please review it and eventually sign? Thanks.
@bsunanda this is something you requested to watch as well.
@rappoccio, @antoniovilela, @sextonkennedy you are the release manager for this.

cms-bot commands are listed here

[fabiocos]

please test

[fabiocos]

type bugfix

[fabiocos]

urgent

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-3cabb5/37615/summary.html
COMMIT: 8f5a675
CMSSW: CMSSW_14_1_X_2024-02-21-1100/el8_amd64_gcc12
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week1/cms-sw/cmssw/44051/37615/install.sh to create a dev area with all the needed externals and cmssw changes.

Comparison Summary

Summary:

• You potentially added 99 lines to the logs
• Reco comparison results: 400 differences found in the comparisons
• DQMHistoTests: Total files compared: 48
• DQMHistoTests: Total histograms compared: 3248389
• DQMHistoTests: Total failures: 1028
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3247339
• DQMHistoTests: Total skipped: 22
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 47 files compared)
• Checked 200 log files, 161 edm output root files, 48 DQM output files
• TriggerResults: no differences found

[bsunanda]

+geometry

[srimanob]

+Upgrade

Does this PR need backport to 14_0?

[fabiocos]

@srimanob this PR will need a backport to 14_0_X only if we want to backport #43762, which entered just in 14_1_0_pre0. But it should hopefully allow us to have a validation of the new code without trouble, and being capable to ask for such a backport without technical pending problems in case.

[fabiocos]

@cms-sw/simulation-l2 any comment?

[civanch]

+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. @rappoccio, @sextonkennedy, @antoniovilela (and backports should be raised in the release meeting by the corresponding L2)

[fabiocos]

@cms-sw/orp-l2 this PR is meant to solve the issue of crashes in recent 14_1_X IBs, the sooner it is merged the sooner we may check and verify this

[rappoccio]

+1