[PWGUD] Fit bit implementation (#15510)

Co-authored-by: amatyja <adam.tomasz.matyja@cern.ch>

Author: sandor-lokos

PWGUD/Core/CMakeLists.txt

@@ -64,3 +64,11 @@ o2physics_add_library(decayTree
 o2physics_target_root_dictionary(decayTree
                                  HEADERS decayTree.h
                                  LINKDEF decayTreeLinkDef.h)
+
+o2physics_add_library(FITCutParHolder
+                      SOURCES FITCutParHolder.cxx
+                      PUBLIC_LINK_LIBRARIES O2::Framework O2Physics::AnalysisCore)
+
+o2physics_target_root_dictionary(FITCutParHolder
+                                 HEADERS FITCutParHolder.h
+                                 LINKDEF FITCutParHolderLinkDef.h)

PWGUD/Core/FITCutParHolder.cxx

@@ -0,0 +1,55 @@
+// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
+// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
+// All rights not expressly granted are reserved.
+//
+// This software is distributed under the terms of the GNU General Public
+// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
+//
+// In applying this license CERN does not waive the privileges and immunities
+// granted to it by virtue of its status as an Intergovernmental Organization
+// or submit itself to any jurisdiction.
+//
+// \FIT bit thresholds
+// \author Sandor Lokos, sandor.lokos@cern.ch
+// \since  March 2026
+
+#include "FITCutParHolder.h"
+
+// setter
+void FITCutParHolder::SetSaveFITbitsets(bool saveFITbitsets)
+{
+  mSaveFITbitsets = saveFITbitsets;
+}
+void FITCutParHolder::SetThr1FV0A(float thr1_FV0A)
+{
+  mThr1FV0A = thr1_FV0A;
+}
+void FITCutParHolder::SetThr1FT0A(float thr1_FT0A)
+{
+  mThr1FT0A = thr1_FT0A;
+}
+void FITCutParHolder::SetThr1FT0C(float thr1_FT0C)
+{
+  mThr1FT0C = thr1_FT0C;
+}
+void FITCutParHolder::SetThr2FV0A(float thr2_FV0A)
+{
+  mThr2FV0A = thr2_FV0A;
+}
+void FITCutParHolder::SetThr2FT0A(float thr2_FT0A)
+{
+  mThr2FT0A = thr2_FT0A;
+}
+void FITCutParHolder::SetThr2FT0C(float thr2_FT0C)
+{
+  mThr2FT0C = thr2_FT0C;
+}
+
+// getter
+bool FITCutParHolder::saveFITbitsets() const { return mSaveFITbitsets; }
+float FITCutParHolder::thr1_FV0A() const { return mThr1FV0A; }
+float FITCutParHolder::thr1_FT0A() const { return mThr1FT0A; }
+float FITCutParHolder::thr1_FT0C() const { return mThr1FT0C; }
+float FITCutParHolder::thr2_FV0A() const { return mThr2FV0A; }
+float FITCutParHolder::thr2_FT0A() const { return mThr2FT0A; }
+float FITCutParHolder::thr2_FT0C() const { return mThr2FT0C; }

PWGUD/Core/FITCutParHolder.h

@@ -0,0 +1,75 @@
+// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
+// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
+// All rights not expressly granted are reserved.
+//
+// This software is distributed under the terms of the GNU General Public
+// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
+//
+// In applying this license CERN does not waive the privileges and immunities
+// granted to it by virtue of its status as an Intergovernmental Organization
+// or submit itself to any jurisdiction.
+//
+// \FIT bit thresholds
+// \author Sandor Lokos, sandor.lokos@cern.ch
+// \since  March 2026
+
+#ifndef PWGUD_CORE_FITCUTPARHOLDER_H_
+#define PWGUD_CORE_FITCUTPARHOLDER_H_
+
+#include <Rtypes.h>
+
+// object to hold customizable FIT bit thresholds
+class FITCutParHolder
+{
+ public:
+  // constructor
+  FITCutParHolder(bool saveFITbitsets = true,
+                  float thr1_FV0A = 8.,
+                  float thr1_FT0A = 8.,
+                  float thr1_FT0C = 8.,
+                  float thr2_FV0A = 20.,
+                  float thr2_FT0A = 20.,
+                  float thr2_FT0C = 20.)
+    : mSaveFITbitsets{saveFITbitsets},
+      mThr1FV0A{thr1_FV0A},
+      mThr1FT0A{thr1_FT0A},
+      mThr1FT0C{thr1_FT0C},
+      mThr2FV0A{thr2_FV0A},
+      mThr2FT0A{thr2_FT0A},
+      mThr2FT0C{thr2_FT0C}
+  {
+  }
+
+  // setters
+  void SetSaveFITbitsets(bool);
+  void SetThr1FV0A(float);
+  void SetThr1FT0A(float);
+  void SetThr1FT0C(float);
+  void SetThr2FV0A(float);
+  void SetThr2FT0A(float);
+  void SetThr2FT0C(float);
+
+  // getters
+  bool saveFITbitsets() const;
+  float thr1_FV0A() const;
+  float thr1_FT0A() const;
+  float thr1_FT0C() const;
+  float thr2_FV0A() const;
+  float thr2_FT0A() const;
+  float thr2_FT0C() const;
+
+ private:
+  bool mSaveFITbitsets;
+
+  float mThr1FV0A;
+  float mThr1FT0A;
+  float mThr1FT0C;
+
+  float mThr2FV0A;
+  float mThr2FT0A;
+  float mThr2FT0C;
+
+  ClassDefNV(FITCutParHolder, 1);
+};
+
+#endif // PWGUD_CORE_FITCUTPARHOLDER_H_

PWGUD/Core/FITCutParHolderLinkDef.h

@@ -0,0 +1,24 @@
+// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
+// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
+// All rights not expressly granted are reserved.
+//
+// This software is distributed under the terms of the GNU General Public
+// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
+//
+// In applying this license CERN does not waive the privileges and immunities
+// granted to it by virtue of its status as an Intergovernmental Organization
+// or submit itself to any jurisdiction.
+//
+// \FIT bit thresholds
+// \author Sandor Lokos, sandor.lokos@cern.ch
+// \since  March 2026
+
+#ifndef PWGUD_CORE_FITCUTPARHOLDERLINKDEF_H_
+#define PWGUD_CORE_FITCUTPARHOLDERLINKDEF_H_
+
+#pragma link off all globals;
+#pragma link off all classes;
+#pragma link off all functions;
+#pragma link C++ class FITCutParHolder + ;
+
+#endif // PWGUD_CORE_FITCUTPARHOLDERLINKDEF_H_

PWGUD/Core/SGCutParHolderLinkDef.h

@@ -8,6 +8,7 @@
 // In applying this license CERN does not waive the privileges and immunities
 // granted to it by virtue of its status as an Intergovernmental Organization
 // or submit itself to any jurisdiction.
+
 #ifndef PWGUD_CORE_SGCUTPARHOLDERLINKDEF_H_
 #define PWGUD_CORE_SGCUTPARHOLDERLINKDEF_H_
 

PWGUD/Core/UDHelpers.h

@@ -19,6 +19,7 @@
 #include "PWGUD/Core/DGCutparHolder.h"
 #include "PWGUD/Core/UPCHelpers.h"
 
+#include "Common/Core/RecoDecay.h"
 #include "Common/DataModel/EventSelection.h"
 #include "Common/DataModel/TrackSelectionTables.h"
 
@@ -29,6 +30,7 @@
 
 #include "TLorentzVector.h"
 
+#include <algorithm>
 #include <bitset>
 #include <vector>
 
@@ -533,6 +535,160 @@ bool FITveto(T const& bc, DGCutparHolder const& diffCuts)
   return false;
 }
 
+inline void setBit(uint64_t w[4], int bit, bool val)
+{
+  if (!val) {
+    return;
+  }
+  const int word = bit >> 6;
+  const int offs = bit & 63;
+  w[word] |= (static_cast<uint64_t>(1) << offs);
+}
+
+template <typename TFT0, typename TFV0A>
+inline void buildFT0FV0Words(TFT0 const& ft0, TFV0A const& fv0a,
+                             uint64_t thr1[4], uint64_t thr2[4],
+                             float thr1_FT0A = 25., float thr1_FT0C = 50., float thr1_FV0A = 50.,
+                             float thr2_FT0A = 50., float thr2_FT0C = 100., float thr2_FV0A = 100.)
+{
+  thr1[0] = thr1[1] = thr1[2] = thr1[3] = 0ull;
+  thr2[0] = thr2[1] = thr2[2] = thr2[3] = 0ull;
+
+  constexpr int kFT0AOffset = 0;
+  constexpr int kFT0COffset = 96;
+  constexpr int kFV0Offset = 208;
+
+  auto ampsA = ft0.amplitudeA();
+  const int nA = std::min<int>(ampsA.size(), 96);
+  for (int i = 0; i < nA; ++i) {
+    const auto a = ampsA[i];
+    setBit(thr1, kFT0AOffset + i, a >= thr1_FT0A);
+    setBit(thr2, kFT0AOffset + i, a >= thr2_FT0A);
+  }
+
+  auto ampsC = ft0.amplitudeC();
+  const int nC = std::min<int>(ampsC.size(), 112);
+  for (int i = 0; i < nC; ++i) {
+    const auto a = ampsC[i];
+    setBit(thr1, kFT0COffset + i, a >= thr1_FT0C);
+    setBit(thr2, kFT0COffset + i, a >= thr2_FT0C);
+  }
+
+  auto ampsV = fv0a.amplitude();
+  const int nV = std::min<int>(ampsV.size(), 48);
+  for (int i = 0; i < nV; ++i) {
+    const auto a = ampsV[i];
+    setBit(thr1, kFV0Offset + i, a >= thr1_FV0A);
+    setBit(thr2, kFV0Offset + i, a >= thr2_FV0A);
+  }
+}
+
+// -----------------------------------------------------------------------------
+// return eta and phi of a given FIT channel based on the bitset
+// Bit layout contract:
+constexpr int kFT0Bits = 208;   // FT0 total channels
+constexpr int kFV0Bits = 48;    // FV0A channels
+constexpr int kTotalBits = 256; // 4*64
+
+// FT0 side split
+constexpr int kFT0AChannels = 96;  // FT0A channels are [0..95]
+constexpr int kFT0CChannels = 112; // FT0C channels are [96..207]
+static_assert(kFT0AChannels + kFT0CChannels == kFT0Bits);
+
+using Bits256 = std::array<uint64_t, 4>;
+
+inline Bits256 makeBits256(uint64_t w0, uint64_t w1, uint64_t w2, uint64_t w3)
+{
+  return {w0, w1, w2, w3};
+}
+
+inline bool testBit(Bits256 const& w, int bit)
+{
+  if (bit < 0 || bit >= kTotalBits) {
+    return false;
+  }
+  return (w[bit >> 6] >> (bit & 63)) & 1ULL;
+}
+
+struct FitBitRef {
+  enum class Det : uint8_t { FT0,
+                             FV0,
+                             Unknown };
+  Det det = Det::Unknown;
+  int ch = -1;      // FT0: 0..207, FV0: 0..47
+  bool isC = false; // only meaningful for FT0
+};
+
+inline FitBitRef decodeFitBit(int bit)
+{
+  FitBitRef out;
+  if (bit >= 0 && bit < kFT0Bits) {
+    out.det = FitBitRef::Det::FT0;
+    out.ch = bit;                     // FT0 channel id
+    out.isC = (bit >= kFT0AChannels); // C side if in upper range
+    return out;
+  }
+  if (bit >= kFT0Bits && bit < kTotalBits) {
+    out.det = FitBitRef::Det::FV0;
+    out.ch = bit - kFT0Bits; // FV0A channel id 0..47
+    return out;
+  }
+  return out;
+}
+
+template <typename FT0DetT, typename OffsetsT>
+inline double getPhiFT0_fromChannel(FT0DetT& ft0Det, int ft0Ch, OffsetsT const& offsetFT0, int i)
+{
+  ft0Det.calculateChannelCenter();
+  auto chPos = ft0Det.getChannelCenter(ft0Ch);
+
+  const double x = chPos.X() + offsetFT0[i].getX();
+  const double y = chPos.Y() + offsetFT0[i].getY();
+
+  return RecoDecay::phi(x, y);
+}
+
+template <typename FT0DetT, typename OffsetsT>
+inline double getEtaFT0_fromChannel(FT0DetT& ft0Det, int ft0Ch, OffsetsT const& offsetFT0, int i)
+{
+  ft0Det.calculateChannelCenter();
+  auto chPos = ft0Det.getChannelCenter(ft0Ch);
+
+  double x = chPos.X() + offsetFT0[i].getX();
+  double y = chPos.Y() + offsetFT0[i].getY();
+  double z = chPos.Z() + offsetFT0[i].getZ();
+
+  // If this channel belongs to FT0C, flip z (matches your original intent)
+  const bool isC = (ft0Ch >= kFT0AChannels);
+  if (isC) {
+    z = -z;
+  }
+
+  const double r = std::sqrt(x * x + y * y);
+  const double theta = std::atan2(r, z);
+  return -std::log(std::tan(0.5 * theta));
+}
+
+template <typename FT0DetT, typename OffsetsT>
+inline bool getPhiEtaFromFitBit(FT0DetT& ft0Det,
+                                int bit,
+                                OffsetsT const& offsetFT0,
+                                int iRunOffset,
+                                double& phi,
+                                double& eta)
+{
+  auto ref = decodeFitBit(bit);
+  if (ref.det != FitBitRef::Det::FT0) {
+    return false;
+  }
+
+  // FT0A: 0..95, FT0C: 96..207
+  const int ft0Ch = bit;
+  phi = getPhiFT0_fromChannel(ft0Det, ft0Ch, offsetFT0, iRunOffset);
+  eta = getEtaFT0_fromChannel(ft0Det, ft0Ch, offsetFT0, iRunOffset);
+  return true;
+}
+
 // -----------------------------------------------------------------------------
 
 template <typename T>

PWGUD/DataModel/UDTables.h

@@ -407,6 +407,31 @@ DECLARE_SOA_TABLE(UDTracksFlags, "AOD", "UDTRACKFLAG",
 DECLARE_SOA_TABLE(UDTracksLabels, "AOD", "UDTRACKLABEL",
                   udtrack::TrackId);
 
+namespace udcollfitbits
+{
+DECLARE_SOA_COLUMN(Thr1W0, thr1W0, uint64_t); /// 1 MIP thresholds for FT0A ch 0 - ch 63
+DECLARE_SOA_COLUMN(Thr1W1, thr1W1, uint64_t); /// 1 MIP thresholds for FT0A ch 64 - ch 96 & FT0C ch 0 - ch 31
+DECLARE_SOA_COLUMN(Thr1W2, thr1W2, uint64_t); /// 1 MIP thresholds for FT0C ch 32 - ch 96
+DECLARE_SOA_COLUMN(Thr1W3, thr1W3, uint64_t); /// 1 MIP thresholds for FT0C ch 97 - 112 & FV0 0 - 47
+
+DECLARE_SOA_COLUMN(Thr2W0, thr2W0, uint64_t); /// 2 MIP thresholds for FT0A ch 0 - ch 63
+DECLARE_SOA_COLUMN(Thr2W1, thr2W1, uint64_t); /// 2 MIP thresholds for FT0A ch 63 - ch 96 & FT0C ch 0 - ch 31
+DECLARE_SOA_COLUMN(Thr2W2, thr2W2, uint64_t); /// 2 MIP thresholds for FT0C ch 32 - ch 96
+DECLARE_SOA_COLUMN(Thr2W3, thr2W3, uint64_t); /// 2 MIP thresholds for FT0C ch 97 - 112 & FV0 0 - 47
+} // namespace udcollfitbits
+
+DECLARE_SOA_TABLE(UDCollisionFITBits, "AOD", "UDCOLLFITBITS",
+                  o2::soa::Index<>,
+                  udcollfitbits::Thr1W0, /// 1 MIP thresholds for FT0A ch 0 - ch 63
+                  udcollfitbits::Thr1W1, /// 1 MIP thresholds for FT0A ch 63 - ch 96 & FT0C ch 0 - ch 31
+                  udcollfitbits::Thr1W2, /// 1 MIP thresholds for FT0C ch 32 - ch 96
+                  udcollfitbits::Thr1W3, /// 1 MIP thresholds for FT0C ch 97 - 112 & FV0 0 - 47
+                  udcollfitbits::Thr2W0, /// 2 MIP thresholds for FT0A ch 0 - ch 63
+                  udcollfitbits::Thr2W1, /// 2 MIP thresholds for FT0A ch 63 - ch 96 & FT0C ch 0 - ch 31
+                  udcollfitbits::Thr2W2, /// 2 MIP thresholds for FT0C ch 32 - ch 96
+                  udcollfitbits::Thr2W3  /// 2 MIP thresholds for FT0C ch 97 - 112 & FV0 0 - 47
+);
+
 using UDTrack = UDTracks::iterator;
 using UDTrackCov = UDTracksCov::iterator;
 using UDTrackExtra = UDTracksExtra::iterator;

PWGUD/TableProducer/CMakeLists.txt

@@ -18,7 +18,7 @@ o2physics_add_dpl_workflow(dg-cand-producer
 
 o2physics_add_dpl_workflow(sgcand-producer
                            SOURCES SGCandProducer.cxx
-                           PUBLIC_LINK_LIBRARIES O2::Framework O2Physics::AnalysisCore O2Physics::SGCutParHolder O2Physics::AnalysisCCDB
+                           PUBLIC_LINK_LIBRARIES O2::Framework O2Physics::AnalysisCore O2Physics::SGCutParHolder O2Physics::AnalysisCCDB O2Physics::FITCutParHolder
                            COMPONENT_NAME Analysis)
 
 o2physics_add_dpl_workflow(dgbccand-producer