[PWGLF] produce derive data

[gengjiabin12]

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[github-actions]

O2 linter results: ❌ 128 errors, ⚠️ 7 warnings, 🔕 0 disabled

[romainschotter]

Hi @gengjiabin12 ! Thank you very much for opening this PR!
Could you please provide a bit more context on what you have in mind? From what I can tell, it seems that you would like to produce derived data for a hadron-strange correlation analysis. Any additional details would be very helpful in fully understanding the changes you are proposing.
Thank you in advance!

[gengjiabin12]

Hi @gengjiabin12 ! Thank you very much for opening this PR! Could you please provide a bit more context on what you have in mind? From what I can tell, it seems that you would like to produce derived data for a hadron-strange correlation analysis. Any additional details would be very helpful in fully understanding the changes you are proposing. Thank you in advance!

Hi experts, Tasks process one Dataframe at once and send out their outputs per-Dataframe.It meants that we will lose a large number of mixedevents when using the CombinationsStrictlyUpperIndexPolicy because a DF file only has a few hundred collisions in PbPb collision.So I want to produce a derived data which only contains the data my analysis needs.As it is much smaller than the original AO2D many data frames (DFs) will be merged together.

[romainschotter]

Hi @gengjiabin12 !

Thank you very much for the additional information.

In that case, it might be worth considering using the existing table producer for hadron-strangeness correlation analyses (hStrangeCorrelationFilter, https://github.com/AliceO2Group/O2Physics/blob/master/PWGLF/TableProducer/Strangeness/hStrangeCorrelationFilter.cxx) rather than adding a new table producer. While this task is not currently used for hadron–strangeness correlation analyses in pp (because the reduction factor is not high enough), it could be interesting to check in Pb-Pb. It may also be useful to check with Kai Cui, who tested the production of derived data in pp and likely have some valuable insights.

Another option (which goes beyond what is currently covered by hStrangeCorrelationFilter) would be to produce linked derived data. In that case, it would probably be best to discuss it first, so we can decide on the best way to proceed.