[PWGCF] add weight calculation from weight histogram and subsampling

[pykuan]

No description provided.

[github-actions]

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

[alibuild]

Error while checking build/O2Physics/code-check for 2d61bf0 at 2026-07-02 14:20:

## sw/BUILD/O2Physics-code-check-latest/log
--
========== List of issues found ==========
++ echo 'Found 94 errors and 4 warnings.'
Found 94 errors and 4 warnings.
++ [[ 94 -gt 0 ]]
++ cat /sw/BUILD/ede590ed0dc5c2a282e5e5898e1a2afc69145da8/O2Physics-code-check/errors.txt
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:97:7: error: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:97:13: error: variable 'eventHistNames' is non-const and globally accessible, consider making it const [cppcoreguidelines-avoid-non-const-global-variables,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:111:7: error: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:111:13: error: variable 'particleHistNames' is non-const and globally accessible, consider making it const [cppcoreguidelines-avoid-non-const-global-variables,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:127:7: error: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:127:13: error: variable 'corrHistNames' is non-const and globally accessible, consider making it const [cppcoreguidelines-avoid-non-const-global-variables,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:139:7: error: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:139:13: error: variable 'centEstmNames' is non-const and globally accessible, consider making it const [cppcoreguidelines-avoid-non-const-global-variables,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:151:7: error: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:151:13: error: variable 'multEstmNames' is non-const and globally accessible, consider making it const [cppcoreguidelines-avoid-non-const-global-variables,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:162:7: error: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:162:13: error: variable 'cutBeforeAfterNames' is non-const and globally accessible, consider making it const [cppcoreguidelines-avoid-non-const-global-variables,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:168:8: error: constructor does not initialize these fields: ccdb, pdg [cppcoreguidelines-pro-type-member-init,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:234:5: error: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:285:5: error: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:290:5: error: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:296:5: error: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:301:5: error: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:308:10: error: no header providing "std::map" is directly included [misc-include-cleaner,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:328:5: error: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:329:5: error: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:335:5: error: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:336:5: error: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:339:10: error: constructor does not initialize these fields: h1, h2, h3, h4, h5, h6, h7, h8 [cppcoreguidelines-pro-type-member-init,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:346:5: error: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:347:5: error: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:501:9: error: do not use 'else' after 'return' [readability-else-after-return,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:507:9: error: do not use 'else' after 'return' [readability-else-after-return,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:570:14: error: use nullptr [modernize-use-nullptr,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:580:14: error: variable 'objectIter' is not initialized [cppcoreguidelines-init-variables,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:585:41: error: do not use reinterpret_cast [cppcoreguidelines-pro-type-reinterpret-cast,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:591:12: error: use nullptr [modernize-use-nullptr,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:599:23: error: use nullptr [modernize-use-nullptr,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:600:27: error: use nullptr [modernize-use-nullptr,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:636:22: error: do not use reinterpret_cast [cppcoreguidelines-pro-type-reinterpret-cast,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:640:24: error: do not use reinterpret_cast [cppcoreguidelines-pro-type-reinterpret-cast,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:650:18: error: do not use reinterpret_cast [cppcoreguidelines-pro-type-reinterpret-cast,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:656:22: error: do not use reinterpret_cast [cppcoreguidelines-pro-type-reinterpret-cast,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:660:24: error: do not use reinterpret_cast [cppcoreguidelines-pro-type-reinterpret-cast,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:690:22: error: do not use reinterpret_cast [cppcoreguidelines-pro-type-reinterpret-cast,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:694:24: error: do not use reinterpret_cast [cppcoreguidelines-pro-type-reinterpret-cast,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:719:26: error: use nullptr [modernize-use-nullptr,-warnings-as-errors]
[0 more errors; see full log]

Full log here.

[vkucera]

@pykuan Please fix your formatting before opening a PR for review.

[pykuan]

Hi @vkucera , MegaLinter and the formatting checks have completed successfully, but the required checks build/O2Physics/o2 and build/O2Physics/o2/macOS-arm are still stuck at "Expected — Waiting for status to be reported". They do not seem to have started. Could you please have a look?

[abilandz]

@pykuan : There is one Required check still failing, but this shall be easy to fix.

[alibuild]

Error while checking build/O2Physics/code-check for e27ed49 at 2026-07-05 04:02:

## sw/BUILD/O2Physics-code-check-latest/log
--
========== List of issues found ==========
++ echo 'Found 6 errors and 0 warnings.'
Found 6 errors and 0 warnings.
++ [[ 6 -gt 0 ]]
++ cat /sw/BUILD/d2e8c2306e4618b2e9cbb98e19dc16b9c807c412/O2Physics-code-check/errors.txt
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:288:102: error: suggest braces around initialization of subobject [clang-diagnostic-missing-braces,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:293:96: error: suggest braces around initialization of subobject [clang-diagnostic-missing-braces,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:304:145: error: suggest braces around initialization of subobject [clang-diagnostic-missing-braces,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:512:7: error: do not use 'else' after 'return' [readability-else-after-return,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:731:26: error: use nullptr [modernize-use-nullptr,-warnings-as-errors]
PWGCF/MultiparticleCorrelations/Tasks/multiparticleCumulants.cxx:1441:5: error: use auto when initializing with new to avoid duplicating the type name [modernize-use-auto,-warnings-as-errors]
++ [[ 0 -gt 0 ]]
++ [[ 6 -gt 0 ]]
++ exit 1
--

Full log here.