[PWGJE] Add diffusion wake analysis by nicola-wilson · Pull Request #16570 · AliceO2Group/O2Physics

nicola-wilson · 2026-06-08T15:12:54Z

This task aims to write tables with collisions that contain at least one high pT track. These are then used by a Bachelor student at GSI who works on diffusion wakes and wants to apply his Run 2 analysis to Run 3 data (therefore, trees are needed). To reduce memory size, some variables are stored in a different format (for example px,py,pz)

github-actions · 2026-06-08T15:13:15Z

O2 linter results: ❌ 1 errors, ⚠️ 0 warnings, 🔕 0 disabled

nzardosh

thanks for the PR :) Please find some comments below

nzardosh · 2026-06-08T15:37:33Z

+{
+
+    // Track properties
+    DECLARE_SOA_COLUMN(ColID, colid, int32_t);        // Collision ID


this should be an index coloumn

nzardosh · 2026-06-08T15:38:52Z

+  }
+
+  using bcs = aod::BCs;
+  void process(soa::Join<aod::Collisions, aod::EvSels,aod::CentFT0Cs, aod::TPCMults, aod::QvectorFT0Cs>::iterator const& col,


It would be great if you could use the JE tables like JCollisions to remove as much dependency as possible on non derived formats

nzardosh · 2026-06-08T15:39:45Z

+                  testtrack::ColID,
+                  testtrack::Charge,
+                  testtrack::P,
+                  testtrack::DEdx,


what is the purpose of this fir diffusion wake studies?

Please consider the following formatting changes to AliceO2Group#16570

vkucera · 2026-06-08T21:27:59Z

+#include <Framework/ASoA.h>
+#include <Framework/AnalysisDataModel.h>
+#include <Framework/AnalysisHelpers.h>
+#include <Framework/AnalysisTask.h>
+#include <Framework/HistogramRegistry.h>
+#include <Framework/HistogramSpec.h>
+#include <Framework/InitContext.h>
+#include <Framework/OutputObjHeader.h>
+#include <Framework/runDataProcessing.h>
+// For centrality:
+#include "Common/DataModel/Centrality.h"
+#include "Common/DataModel/EventSelection.h"
+// For TPC Mult
+#include "Common/DataModel/Multiplicity.h"
+// For DCA and TrackSelection
+#include "Common/DataModel/TrackSelectionTables.h"
+// For EP
+#include "Common/Core/EventPlaneHelper.h"
+#include "Common/DataModel/Qvectors.h"
+// For occupancy bit
+#include "Common/CCDB/EventSelectionParams.h"


Remove all comments (or move them to the ends of lines). They block the sorting and grouping.

Also make sure you include exactly what you use.

vkucera · 2026-06-08T21:28:45Z

 o2physics_add_dpl_workflow(jet-deriveddata-producer
-                    SOURCES derivedDataProducer.cxx
+                    SOURCES jetDeriveddataProducer.cxx


These files are not modified in this PR.

vkucera

Fix the errors and warnings introduced by your PR.

fjonasALICE · 2026-06-09T07:05:13Z

+      histos.fill(HIST("etaHistogram"), track.eta());
+      histos.fill(HIST("pTHistogram"), track.pt());
+
+      //------------ Translate values to less memory consuming values --------------------


it is a nice idea to do this type of packing, however, I see no guards against maximum values. Are you sure no reasonable values can cause an overflow of your bits allocated for packing?

What is the reduction factor?

fjonasALICE · 2026-06-09T07:06:36Z

+  void init(InitContext const&)
+  {
+    const AxisSpec axisEta{30, -1.5, +1.5, "#eta"};
+    const AxisSpec axispT{nBinsPt, 0, 10, "p_{T}"};


are you sure you want pt only to be 0-10? this seems too small to me, do you mean 100 GeV?

Updated pT axis range to accommodate higher values and added overflow checks for track momentum.

Removed unused track properties and added collision index column.

Removed unused includes and commented out a declaration.

Updated data types for various variables to improve memory usage and consistency. Changed float and short types to more appropriate fixed-width integer types.

Removed commented-out block detailing track and event data compression before and after compression.

Added file documentation for clarity.

Replaced C-style casts with C++ style static_cast for type safety.

vkucera · 2026-06-09T14:59:25Z

Revert the .mega-linter.yml. modification. If you want to update your branch, do it properly as per the instructions.

vkucera · 2026-06-09T15:01:41Z

This file is not a table definition, it's a table producer, so don't start the name with table....

vkucera · 2026-06-09T15:02:41Z

+      if (particlePx < 0)
+        substituteP |= static_cast<uint64_t>1 << uppermostBit;
+      if (particlePx < 0)
+        particlePx = (-1) * particlePx;
+      for (int8_t i_bit = lowermostBit; i_bit < uppermostBit; i_bit++) {
+        if ((particlePx & (static_cast<int64_t>1 << i_bit)))
+          substituteP |= static_cast<uint64_t>1 << i_bit;


This does not look like a valid cast syntax. Why don't you just use SETBIT?

Why wouldn't it? Looks fine to me

Because it does not compile.

I have made the mapping simpler now

How did you test it?

Removed REPOSITORY_OSV_SCANNER from the configuration.

Removed author information from comments.

vkucera · 2026-06-09T15:38:26Z

@wirthni Who are you?

Replaced bitwise operations in Px, Py, and Pz calculations with bitmasking for efficiency.

wirthni · 2026-06-09T16:02:44Z

@wirthni Who are you?

I'm a bachelor's student of Nicola Wilson

vkucera · 2026-06-09T16:12:34Z

@wirthni Who are you?

I'm a bachelor's student of Nicola Wilson

Please add your full name on your GitHub profile. Your colleagues should know who is contributing in the code.

vkucera · 2026-06-09T16:59:35Z

+    histos.add("pTHistogram", "pTHistogram", kTH1F, {axispT});
+  }
+
+  using Bcs = aod::BCs;


Why do you need this alias?

vkucera · 2026-06-09T16:59:51Z

+               soa::Join<aod::TracksIU, aod::TracksExtra, aod::TracksDCA, aod::TrackSelection> const& tracks,
+               Bcs const&)
+  {
+    const float maxMomentum = 173.0;


Where does this come from?

vkucera · 2026-06-09T17:01:33Z

+// or submit itself to any jurisdiction.
+///
+/// \file tableDiffWake.cxx
+/// \brief This task writes a collision and track table which are further used in a diffusion wake analysis


Where is the analysis task?

nicola-wilson added 3 commits May 19, 2026 14:16

Added table producer example

9a39814

PWGJE: add tableDiffWake task

8e49699

PWGJE: add tableDiffWake task - restored myExample

b6b1b56

nicola-wilson requested review from alibuild, fjonasALICE, maoyx, mfasDa, mhemmer-cern, nzardosh and raymondEhlers as code owners June 8, 2026 15:12

github-actions Bot added the pwgje label Jun 8, 2026

alibuild mentioned this pull request Jun 8, 2026

Please consider the following formatting changes to #16570 nicola-wilson/O2Physics#1

Closed

nzardosh reviewed Jun 8, 2026

View reviewed changes

nicola-wilson and others added 5 commits June 8, 2026 17:42

Updated format tableDiffWake

5edc2ad

Updated format tableDiffWake 2

25d674a

Updated format tableDiffWake 3

13f091f

Updated format tableDiffWake 4

e90d684

Change data types for several SOA columns

6542d38

alibuild mentioned this pull request Jun 8, 2026

Please consider the following formatting changes to #16570 nicola-wilson/O2Physics#2

Merged

wirthni and others added 4 commits June 8, 2026 21:53

Rename source files in CMakeLists.txt for jet workflows

431f51b

Fix formatting of P column declaration

2780af4

Please consider the following formatting changes

e993d81

Merge pull request #2 from alibuild/alibot-cleanup-16570

e74c748

Please consider the following formatting changes to AliceO2Group#16570

vkucera requested changes Jun 8, 2026

View reviewed changes

vkucera marked this pull request as draft June 8, 2026 21:29

vkucera requested changes Jun 8, 2026

View reviewed changes

fjonasALICE requested changes Jun 9, 2026

View reviewed changes

Disable OSV Scanner

9ece9fb

github-actions Bot added the infrastructure label Jun 9, 2026

Adjust pT axis and add momentum overflow checks

c139b63

Updated pT axis range to accommodate higher values and added overflow checks for track momentum.

alibuild mentioned this pull request Jun 9, 2026

Please consider the following formatting changes to #16570 nicola-wilson/O2Physics#3

Closed

wirthni added 3 commits June 9, 2026 11:05

Refactor tableDiffWake.cxx to clean up track properties

ba83b1e

Removed unused track properties and added collision index column.

Clean up includes and fix comment space

fd23dc5

Removed unused includes and commented out a declaration.

Refactor variable types for memory optimization

3205395

Updated data types for various variables to improve memory usage and consistency. Changed float and short types to more appropriate fixed-width integer types.

alibuild mentioned this pull request Jun 9, 2026

Please consider the following formatting changes to #16570 nicola-wilson/O2Physics#4

Open

wirthni added 7 commits June 9, 2026 16:05

Refactor variable names for clarity in tableDiffWake

1b2127a

rewrote comments

86d80c6

Removed commented-out block detailing track and event data compression before and after compression.

Refactor configurable parameters in tableDiffWake

2874fa1

Enhance documentation in tableDiffWake.cxx

691c4f3

Added file documentation for clarity.

Rename configurable variables and type alias

20a8eb1

Rename struct tableDiffWake to TableDiffWake

cf17915

Refactor casts to use static_cast

59f4542

Replaced C-style casts with C++ style static_cast for type safety.

vkucera reviewed Jun 9, 2026

View reviewed changes

vkucera changed the title ~~[PWGJE] Created new task: Produce tables for diffusion wake analysis~~ [PWGJE] Add diffusion wake analysis Jun 9, 2026

Remove REPOSITORY_OSV_SCANNER from mega-linter

141512f

Removed REPOSITORY_OSV_SCANNER from the configuration.

github-actions Bot removed the infrastructure label Jun 9, 2026

wirthni added 3 commits June 9, 2026 17:34

Refactor track iteration to use 'const auto&'

cd6e89e

Remove unnecessary comment section in tableDiffWake.cxx

397e95e

Clean up comments in tableDiffWake.cxx

45bfab2

Removed author information from comments.

Optimize particle momentum calculations using bitmasking

df6997d

Replaced bitwise operations in Px, Py, and Pz calculations with bitmasking for efficiency.

vkucera reviewed Jun 9, 2026

View reviewed changes

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