[PWGCF] JCorran: Add nonflow SPC correlators and a smaller Q-vector f…

[nmallick19]

1. Code for C0- and C1-scaling terms for non-flow subtraction added
2. New non-flow estimators C112, C123, C1{4}
3. Q-Vector grid size is optimized with SPC type (3- or 4-particle) to reduce computational cost

[github-actions]

O2 linter results: ❌ 0 errors, ⚠️ 38 warnings, 🔕 0 disabled

[alibuild]

Error while checking build/O2Physics/code-check for 91e561c at 2026-09-30 19:25:

## sw/BUILD/O2Physics-code-check-latest/log
--
========== List of issues found ==========
++ echo 'Found 4 errors and 129 warnings.'
Found 4 errors and 129 warnings.
++ [[ 4 -gt 0 ]]
++ cat /sw/BUILD/4dbf2559f5fb9966f7296a5c4ef964c911a214b2/O2Physics-code-check/errors.txt
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:123:5: error: Value stored to 'correlationNum' is never read [clang-analyzer-deadcode.DeadStores,-warnings-as-errors]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:124:5: error: Value stored to 'weightCorrelationNum' is never read [clang-analyzer-deadcode.DeadStores,-warnings-as-errors]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:125:5: error: Value stored to 'correlationDenom' is never read [clang-analyzer-deadcode.DeadStores,-warnings-as-errors]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:126:5: error: Value stored to 'weightCorrelationDenom' is never read [clang-analyzer-deadcode.DeadStores,-warnings-as-errors]
++ [[ 129 -gt 0 ]]
++ cat /sw/BUILD/4dbf2559f5fb9966f7296a5c4ef964c911a214b2/O2Physics-code-check/warnings.txt
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:27:18: warning: statement should be inside braces [readability-braces-around-statements]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:42:16: warning: statement should be inside braces [readability-braces-around-statements]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:45:19: warning: statement should be inside braces [readability-braces-around-statements]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:70:17: warning: statement should be inside braces [readability-braces-around-statements]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:81:3: warning: use auto when initializing with new to avoid duplicating the type name [modernize-use-auto]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:82:10: warning: variable 'correlationNum' is not initialized [cppcoreguidelines-init-variables]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:83:10: warning: variable 'weightCorrelationNum' is not initialized [cppcoreguidelines-init-variables]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:84:10: warning: variable 'correlationDenom' is not initialized [cppcoreguidelines-init-variables]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:85:10: warning: variable 'weightCorrelationDenom' is not initialized [cppcoreguidelines-init-variables]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:87:31: warning: statement should be inside braces [readability-braces-around-statements]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:96:5: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:100:40: warning: 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]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:106:5: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:112:31: warning: 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]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:117:142: warning: statement should be inside braces [readability-braces-around-statements]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:280:3: warning: switching on non-enum value without default case may not cover all cases [bugprone-switch-missing-default-case]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:282:7: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:283:7: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:285:12: warning: implicit conversion 'double' -> 'bool' [readability-implicit-bool-conversion]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:285:12: warning: narrowing conversion from 'double' to 'bool' [bugprone-narrowing-conversions]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:286:41: warning: 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]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:289:44: warning: 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]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:296:7: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:297:7: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:299:12: warning: implicit conversion 'double' -> 'bool' [readability-implicit-bool-conversion]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:299:12: warning: narrowing conversion from 'double' to 'bool' [bugprone-narrowing-conversions]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:300:41: warning: 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]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:303:46: warning: 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]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:310:7: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:311:7: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:313:12: warning: implicit conversion 'double' -> 'bool' [readability-implicit-bool-conversion]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:313:12: warning: narrowing conversion from 'double' to 'bool' [bugprone-narrowing-conversions]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:314:41: warning: 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]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:317:45: warning: 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]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:324:7: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGCF/JCorran/Core/FlowJSPCAnalysis.cxx:325:7: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
[0 more errors; see full log]

Full log here.