[PWGLF] Update MC centrality task

[romainschotter]

• extend MC centrality to all available estimators

• re-write MC centrality assignment using MC multiplicities calculated in the multCentTable.cxx

• factorize MC centrality task into a class module in order to be usable when running over original data AND derived data (assuming that the derived data contains a table with all of the following getters: multMCFT0A(), multMCFT0C(), multMCFV0A(), multMCFDDA(), multMCFDDC(), multMCNParticlesEta08(), multMCNParticlesEta05()). This allows to NOT store the MC centrality in derived data but simply to store the MC multiplicity and later calculate the MC centrality on the fly.

• add auto-detection features

• allow MC centrality calibration to be extracted on the fly in order to find the MC centrality bins ensuring the best matching between the recoed multiplicity in data and MC

• provide an alternative MC centrality calibration mode: instead of extracting the MC centrality calibration going from low-multiplicity to high-multiplicity collisions, start from the high-multiplicity collisions (where the difference in MC multiplicities is bigger from one class to the next) to the low-multiplicity collisions. This ensures a more stable extraction of the MC centrality calibration and an overall better matching of the recoed multiplicity in data and MC as show below

• provide an alternative assignment of the MC centrality, inspired from the approach in the analyses in light- and heavy-ion collisions. In OO and Pb-Pb collisions, the correlations between centrality and a generated quantity (typically MC multiplicity in |eta|< 0.5) is used. This allows to extract the conditional probability P(MC multiplicity|centrality) (see left figure), which can be used to assign statistically a centrality value to generated collisions by multiplying the any quantity as a function of the MC multiplicity by the corresponding probability distribution within the considered centrality bin. Another approach to assign a centrality value on a candidate-by-candidate basis is to extract the conditional probability P(centrality| MC multiplicity) (see right figure) and, for a given MC multiplicity, sample the corresponding probability distribution to extract a centrality value. The latter approach has now been implemented in the MC centrality task and can be used by turning on assignCentralityPerCandidate.

NOTE1: this latter approach assumes that there is already a good matching in the recoed multiplicity in data and MC in all centrality bins.
NOTE2: the latter approach has the advantage that it works for any centrality binning, which is not the case for the other approaches in the MC centrality task.

• update derivedlambdakzeroanalysis.cxx in order to use the MC centrality (for testing)

@ddobrigk @njacazio @ercolessi for your information

[github-actions]

O2 linter results: ❌ 179 errors, ⚠️ 69 warnings, 🔕 0 disabled

[alibuild]

Error while checking build/O2Physics/staging for 7648416 at 2026-08-26 02:50:

## sw/BUILD/O2Physics-latest/log
c++: fatal error: Killed signal terminated program cc1plus
c++: fatal error: Killed signal terminated program cc1plus
c++: fatal error: Killed signal terminated program cc1plus
ninja: build stopped: subcommand failed.

Full log here.

[alibuild]

Error while checking build/O2Physics/code-check for 7648416 at 2026-08-26 08:34:

## sw/BUILD/O2Physics-code-check-latest/log
--
========== List of issues found ==========
++ echo 'Found 27 errors and 196 warnings.'
Found 27 errors and 196 warnings.
++ [[ 27 -gt 0 ]]
++ cat /sw/BUILD/8d0509c6128a3727b995b889fb9f9d4c1ddef571/O2Physics-code-check/errors.txt
PWGLF/TableProducer/Common/mcCentrality.cxx:41:8: error: constructor does not initialize these fields: ccdb [cppcoreguidelines-pro-type-member-init,-warnings-as-errors]
PWGLF/TableProducer/Strangeness/strangederivedbuilder.cxx:82:9: error: function-like macro 'bitset' used; consider a 'constexpr' template function [cppcoreguidelines-macro-usage,-warnings-as-errors]
PWGLF/TableProducer/Strangeness/strangederivedbuilder.cxx:83:9: error: function-like macro 'bitcheck' used; consider a 'constexpr' template function [cppcoreguidelines-macro-usage,-warnings-as-errors]
PWGLF/TableProducer/Strangeness/strangederivedbuilder.cxx:85:8: error: constructor does not initialize these fields: pdg [cppcoreguidelines-pro-type-member-init,-warnings-as-errors]
PWGLF/TableProducer/Strangeness/strangederivedbuilder.cxx:182:56: error: do not implicitly decay an array into a pointer; consider using gsl::array_view or an explicit cast instead [cppcoreguidelines-pro-bounds-array-to-pointer-decay,-warnings-as-errors]
PWGLF/TableProducer/Strangeness/strangederivedbuilder.cxx:291:39: error: the parameter 'collision' is copied for each invocation but only used as a const reference; consider making it a const reference [performance-unnecessary-value-param,-warnings-as-errors]
PWGLF/TableProducer/Strangeness/strangenessMcCentrality.cxx:37:8: error: constructor does not initialize these fields: ccdb [cppcoreguidelines-pro-type-member-init,-warnings-as-errors]
PWGLF/Tasks/Strangeness/derivedlambdakzeroanalysis.cxx:91:9: error: function-like macro 'BITSET' used; consider a 'constexpr' template function [cppcoreguidelines-macro-usage,-warnings-as-errors]
PWGLF/Tasks/Strangeness/derivedlambdakzeroanalysis.cxx:92:9: error: function-like macro 'BITCHECK' used; consider a 'constexpr' template function [cppcoreguidelines-macro-usage,-warnings-as-errors]
PWGLF/Tasks/Strangeness/derivedlambdakzeroanalysis.cxx:103:8: error: constructor does not initialize these fields: isRun3, ccdb, mRunNumber, magField, maskTopological, maskTopoNoV0Radius, maskTopoNoDCANegToPV, maskTopoNoDCAPosToPV, maskTopoNoCosPA, maskTopoNoDCAV0Dau, maskTrackProperties, maskK0ShortSpecific, maskLambdaSpecific, maskAntiLambdaSpecific, maskSelectionK0Short, maskSelectionLambda, maskSelectionAntiLambda, secondaryMaskSelectionLambda, secondaryMaskSelectionAntiLambda [cppcoreguidelines-pro-type-member-init,-warnings-as-errors]
PWGLF/Tasks/Strangeness/derivedlambdakzeroanalysis.cxx:203:67: error: do not implicitly decay an array into a pointer; consider using gsl::array_view or an explicit cast instead [cppcoreguidelines-pro-bounds-array-to-pointer-decay,-warnings-as-errors]
PWGLF/Tasks/Strangeness/derivedlambdakzeroanalysis.cxx:1349:28: error: the parameter 'collision' is copied for each invocation but only used as a const reference; consider making it a const reference [performance-unnecessary-value-param,-warnings-as-errors]
PWGLF/Tasks/Strangeness/derivedlambdakzeroanalysis.cxx:1410:44: error: the parameter 'v0' is copied for each invocation but only used as a const reference; consider making it a const reference [performance-unnecessary-value-param,-warnings-as-errors]
PWGLF/Tasks/Strangeness/derivedlambdakzeroanalysis.cxx:1410:59: error: the parameter 'collision' is copied for each invocation but only used as a const reference; consider making it a const reference [performance-unnecessary-value-param,-warnings-as-errors]
PWGLF/Tasks/Strangeness/derivedlambdakzeroanalysis.cxx:1673:37: error: the parameter 'v0' is copied for each invocation but only used as a const reference; consider making it a const reference [performance-unnecessary-value-param,-warnings-as-errors]
PWGLF/Tasks/Strangeness/derivedlambdakzeroanalysis.cxx:1856:29: error: the parameter 'v0' is copied for each invocation but only used as a const reference; consider making it a const reference [performance-unnecessary-value-param,-warnings-as-errors]
PWGLF/Tasks/Strangeness/derivedlambdakzeroanalysis.cxx:2259:46: error: the parameter #1 is copied for each invocation but only used as a const reference; consider making it a const reference [performance-unnecessary-value-param,-warnings-as-errors]
PWGLF/Tasks/Strangeness/derivedlambdakzeroanalysis.cxx:2282:31: error: the parameter 'v0' is copied for each invocation but only used as a const reference; consider making it a const reference [performance-unnecessary-value-param,-warnings-as-errors]
PWGLF/Tasks/Strangeness/derivedlambdakzeroanalysis.cxx:2336:35: error: the parameter 'collision' is copied for each invocation but only used as a const reference; consider making it a const reference [performance-unnecessary-value-param,-warnings-as-errors]
PWGLF/Utils/mcCentralityModule.h:53:1: error: using declarations in the global namespace in headers are prohibited [google-global-names-in-headers,-warnings-as-errors]
PWGLF/Utils/mcCentralityModule.h:54:1: error: using declarations in the global namespace in headers are prohibited [google-global-names-in-headers,-warnings-as-errors]
PWGLF/Utils/mcCentralityModule.h:55:1: error: using declarations in the global namespace in headers are prohibited [google-global-names-in-headers,-warnings-as-errors]
PWGLF/Utils/mcCentralityModule.h:123:80: error: do not implicitly decay an array into a pointer; consider using gsl::array_view or an explicit cast instead [cppcoreguidelines-pro-bounds-array-to-pointer-decay,-warnings-as-errors]
PWGLF/Utils/mcCentralityModule.h:385:17: error: do not use reinterpret_cast [cppcoreguidelines-pro-type-reinterpret-cast,-warnings-as-errors]
PWGLF/Utils/mcCentralityModule.h:402:32: error: the parameter 'estimator' is copied for each invocation but only used as a const reference; consider making it a const reference [performance-unnecessary-value-param,-warnings-as-errors]
PWGLF/Utils/mcCentralityModule.h:455:28: error: narrowing conversion from 'Double_t' (aka 'double') to 'int' [bugprone-narrowing-conversions,-warnings-as-errors]
PWGLF/Utils/mcCentralityModule.h:529:28: error: narrowing conversion from 'Double_t' (aka 'double') to 'int' [bugprone-narrowing-conversions,-warnings-as-errors]
++ [[ 196 -gt 0 ]]
++ cat /sw/BUILD/8d0509c6128a3727b995b889fb9f9d4c1ddef571/O2Physics-code-check/warnings.txt
PWGLF/DataModel/LFStrangenessTables.h:80:72: warning: redundant boolean literal in ternary expression result [readability-simplify-boolean-expr]
PWGLF/DataModel/LFStrangenessTables.h:694:52: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGLF/DataModel/LFStrangenessTables.h:695:52: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGLF/DataModel/LFStrangenessTables.h:696:48: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGLF/DataModel/LFStrangenessTables.h:697:48: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGLF/DataModel/LFStrangenessTables.h:698:52: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGLF/DataModel/LFStrangenessTables.h:699:52: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGLF/DataModel/LFStrangenessTables.h:1337:37: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGLF/DataModel/LFStrangenessTables.h:1341:37: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGLF/DataModel/LFStrangenessTables.h:1344:50: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGLF/DataModel/LFStrangenessTables.h:1345:54: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGLF/DataModel/LFStrangenessTables.h:1346:66: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGLF/DataModel/LFStrangenessTables.h:1347:66: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
[0 more errors; see full log]

Full log here.

[alibuild]

Error while checking build/O2Physics/o2 for cb93b45 at 2026-08-26 11:49:

## sw/BUILD/O2Physics-latest/log
c++: fatal error: Killed signal terminated program cc1plus
c++: fatal error: Killed signal terminated program cc1plus
c++: fatal error: Killed signal terminated program cc1plus
ninja: build stopped: subcommand failed.

Full log here.