GPU: Automatically adapt cuts depending on Bz in TPC tracking

Author: davidrohr

GPU/GPUTracking/Base/GPUParam.cxx

@@ -134,11 +134,16 @@ void GPUParam::UpdateGRPSettings(const GPUSettingsGRP* g, const GPUSettingsProce
       GPUTPCGMPolynomialFieldManager::GetPolynomialField(par.bzkG, polynomialField);
     }
   }
+  par.earlyTpcTransform = rec.tpc.forceEarlyTransform == -1 ? (!par.continuousTracking) : rec.tpc.forceEarlyTransform;
+  par.qptB5Scaler = CAMath::Abs(par.bzkG) > 0.1 ? CAMath::Abs(par.bzkG) / 5.006680f : 1.f;
   if (p) {
     par.debugLevel = p->debugLevel;
     par.resetTimers = p->resetTimers;
+    if (p->automaticQPtThresholds) {
+      rec.maxTrackQPt = 1.f / GPUCA_MIN_TRACK_PTB5_DEFAULT / par.qptB5Scaler;
+      rec.tpc.rejectQPt = 1.f / GPUCA_MIN_TRACK_PTB5_REJECT / par.qptB5Scaler;
+    }
   }
-  par.earlyTpcTransform = rec.tpc.forceEarlyTransform == -1 ? (!par.continuousTracking) : rec.tpc.forceEarlyTransform;
 }
 
 void GPUParam::SetDefaults(const GPUSettingsGRP* g, const GPUSettingsRec* r, const GPUSettingsProcessing* p, const GPURecoStepConfiguration* w)

GPU/GPUTracking/Definitions/GPUDefConstantsAndSettings.h

@@ -30,17 +30,17 @@
   #error Invalid Compile Definitions, need to build for either AliRoot or O2 or Standalone
 #endif
 
-#define GPUCA_TRACKLET_SELECTOR_MIN_HITS(QPT) (CAMath::Abs(QPT) > 10 ? 10 : (CAMath::Abs(QPT) > 5 ? 15 : 29)) // Minimum hits should depend on Pt, low Pt tracks can have few hits. 29 Hits default, 15 for < 200 mev, 10 for < 100 mev
+#define GPUCA_TRACKLET_SELECTOR_MIN_HITS_B5(QPTB5) (CAMath::Abs(QPTB5) > 10 ? 10 : (CAMath::Abs(QPTB5) > 5 ? 15 : 29)) // Minimum hits should depend on Pt, low Pt tracks can have few hits. 29 Hits default, 15 for < 200 mev, 10 for < 100 mev
 
 #define GPUCA_GLOBAL_TRACKING_RANGE 45                // Number of rows from the upped/lower limit to search for global track candidates in for
-#define GPUCA_GLOBAL_TRACKING_Y_RANGE_UPPER 0.85      // Inner portion of y-range in slice that is not used in searching for global track candidates
-#define GPUCA_GLOBAL_TRACKING_Y_RANGE_LOWER 0.85
+#define GPUCA_GLOBAL_TRACKING_Y_RANGE_UPPER 0.85f     // Inner portion of y-range in slice that is not used in searching for global track candidates
+#define GPUCA_GLOBAL_TRACKING_Y_RANGE_LOWER 0.85f
 #define GPUCA_GLOBAL_TRACKING_MIN_ROWS 10             // Min num of rows an additional global track must span over
 #define GPUCA_GLOBAL_TRACKING_MIN_HITS 8              // Min num of hits for an additional global track
 
 #define GPUCA_MERGER_CE_ROWLIMIT 5                    //Distance from first / last row in order to attempt merging accross CE
-#define GPUCA_MERGER_LOOPER_QPT_LIMIT 4               // Min Q/Pt to run special looper merging procedure
-#define GPUCA_MERGER_HORIZONTAL_DOUBLE_QPT_LIMIT 2    // Min Q/Pt to attempt second horizontal merge between slices after a vertical merge was found
+#define GPUCA_MERGER_LOOPER_QPTB5_LIMIT 4             // Min Q/Pt (@B=0.5T) to run special looper merging procedure
+#define GPUCA_MERGER_HORIZONTAL_DOUBLE_QPTB5_LIMIT 2  // Min Q/Pt (@B=0.5T) to attempt second horizontal merge between slices after a vertical merge was found
 #define GPUCA_MERGER_MAX_TRACK_CLUSTERS 1000          // Maximum number of clusters a track may have after merging
 
 #define GPUCA_Y_FACTOR 4                              // Weight of y residual vs z residual in tracklet constructor
@@ -49,7 +49,8 @@
 #define GPUCA_TRACKLET_CONSTRUCTOR_MAX_ROW_GAP_SEED 2 // Same, but during fit of seed
 #define GPUCA_MERGER_MAXN_MISSED_HARD 10              // Hard limit for number of missed rows in fit / propagation
 #define GPUCA_MERGER_COV_LIMIT 1000                   // Abort fit when y/z cov exceed the limit
-#define GPUCA_MIN_TRACK_PT_DEFAULT 0.010              // Default setting for minimum track Pt at some places
+#define GPUCA_MIN_TRACK_PTB5_DEFAULT 0.010            // Default setting for minimum track Pt at some places (at B=0.5T)
+#define GPUCA_MIN_TRACK_PTB5_REJECT 0.050f            // Default setting for Pt (at B=0.5T) where tracks are rejected
 
 #define GPUCA_MAX_SIN_PHI_LOW 0.99f                   // Limits for maximum sin phi during fit
 #define GPUCA_MAX_SIN_PHI 0.999f                      // Must be preprocessor define because c++ pre 11 cannot use static constexpr for initializes

GPU/GPUTracking/Definitions/GPUSettingsList.h

@@ -36,7 +36,7 @@ BeginNamespace(gpu)
 // Settings concerning the reconstruction
 // There must be no bool in here, use char, as sizeof(bool) is compiler dependent and fails on GPUs!!!!!!
 BeginSubConfig(GPUSettingsRecTPC, tpc, configStandalone.rec, "RECTPC", 0, "Reconstruction settings", rec_tpc)
-AddOptionRTC(rejectQPt, float, 1.f / 0.05f, "", 0, "QPt threshold to reject clusters of TPC tracks (Inverse Pt!!!)")
+AddOptionRTC(rejectQPt, float, 1.f / GPUCA_MIN_TRACK_PTB5_REJECT, "", 0, "QPt threshold to reject clusters of TPC tracks (Inverse Pt!!!)")
 AddOptionRTC(hitPickUpFactor, float, 2., "", 0, "multiplier for the chi2 window for hit pick up procedure")
 AddOptionRTC(neighboursSearchArea, float, 3., "", 0, "area in cm for the search of neighbours")
 AddOptionRTC(clusterError2CorrectionY, float, 1., "", 0, "correction for the squared cluster error during tracking")
@@ -91,7 +91,7 @@ AddHelp("help", 'h')
 EndConfig()
 
 BeginSubConfig(GPUSettingsRec, rec, configStandalone, "REC", 0, "Reconstruction settings", rec)
-AddOptionRTC(maxTrackQPt, float, 1.f / GPUCA_MIN_TRACK_PT_DEFAULT, "", 0, "required max Q/Pt (==min Pt) of tracks")
+AddOptionRTC(maxTrackQPt, float, 1.f / GPUCA_MIN_TRACK_PTB5_DEFAULT, "", 0, "required max Q/Pt (==min Pt) of tracks")
 AddOptionRTC(nonConsecutiveIDs, char, false, "", 0, "Non-consecutive cluster IDs as in HLT, disables features that need access to slice data in TPC merger")
 AddOptionRTC(fwdTPCDigitsAsClusters, unsigned char, 0, "", 0, "Forward TPC digits as clusters (if they pass the ZS threshold)")
 AddOptionRTC(bz0Pt, unsigned char, 60, "", 0, "Nominal Pt to set when bz = 0 (in 10 MeV)")
@@ -167,6 +167,7 @@ AddOption(clearO2OutputFromGPU, bool, false, "", 0, "Free the GPU memory used fo
 AddOption(ignoreNonFatalGPUErrors, bool, false, "", 0, "Continue running after having received non fatal GPU errors, e.g. abort due to overflow")
 AddOption(tpcIncreasedMinClustersPerRow, unsigned int, 0, "", 0, "Impose a minimum buffer size for the clustersPerRow during TPC clusterization")
 AddOption(noGPUMemoryRegistration, bool, false, "", 0, "Do not register input / output memory for GPU dma transfer")
+AddOption(automaticQPtThresholds, bool, true, "", 0, "Update the QPt thresholde at initialization accoding to the B field (i.e. lower to 40% for B=0.2T)")
 AddVariable(eventDisplay, GPUCA_NAMESPACE::gpu::GPUDisplayBackend*, nullptr)
 AddSubConfig(GPUSettingsProcessingRTC, rtc)
 AddHelp("help", 'h')
@@ -424,6 +425,7 @@ AddVariableRTC(dodEdx, char, 0)              // Do dEdx computation
 AddVariableRTC(earlyTpcTransform, char, 0)   // do Early TPC transformation
 AddVariableRTC(debugLevel, char, 0)          // Debug level
 AddVariableRTC(continuousMaxTimeBin, int, 0) // Max time bin for continuous tracking
+AddVariableRTC(qptB5Scaler, float, 1.f)      // Scaling factor for QPt to B=0.5T
 EndConfig()
 
 EndNamespace() // gpu

GPU/GPUTracking/Merger/GPUTPCGMMerger.cxx

@@ -679,7 +679,7 @@ GPUd() void GPUTPCGMMerger::MakeBorderTracks(int nBlocks, int nThreads, int iBlo
       continue;
     }
     if (useOrigTrackParam) { // TODO: Check how far this makes sense with slice track refit
-      if (CAMath::Abs(track->QPt()) < GPUCA_MERGER_LOOPER_QPT_LIMIT) {
+      if (CAMath::Abs(track->QPt()) * Param().par.qptB5Scaler < GPUCA_MERGER_LOOPER_QPTB5_LIMIT) {
         continue;
       }
       const GPUTPCGMSliceTrack* trackMin = track;
@@ -697,7 +697,7 @@ GPUd() void GPUTPCGMMerger::MakeBorderTracks(int nBlocks, int nThreads, int iBlo
         trackTmp.Set(this, trackMin->OrigTrack(), trackMin->Alpha(), trackMin->Slice());
       }
     } else {
-      if (CAMath::Abs(track->QPt()) < GPUCA_MERGER_HORIZONTAL_DOUBLE_QPT_LIMIT) {
+      if (CAMath::Abs(track->QPt()) * Param().par.qptB5Scaler < GPUCA_MERGER_HORIZONTAL_DOUBLE_QPTB5_LIMIT) {
         if (iBorder == 0 && track->NextNeighbour() >= 0) {
           continue;
         }
@@ -735,7 +735,7 @@ GPUd() void GPUTPCGMMerger::MergeBorderTracks<0>(int nBlocks, int nThreads, int
   for (int itr = iBlock * nThreads + iThread; itr < N1; itr += nThreads * nBlocks) {
     GPUTPCGMBorderTrack& b = B1[itr];
     float d = CAMath::Max(0.5f, 3.5f * CAMath::Sqrt(b.Cov()[1]));
-    if (CAMath::Abs(b.Par()[4]) >= 20) {
+    if (CAMath::Abs(b.Par()[4]) * Param().par.qptB5Scaler >= 20) {
       d *= 2;
     } else if (d > 3) {
       d = 3;
@@ -755,7 +755,7 @@ GPUd() void GPUTPCGMMerger::MergeBorderTracks<0>(int nBlocks, int nThreads, int
     for (int itr = iBlock * nThreads + iThread; itr < N2; itr += nThreads * nBlocks) {
       GPUTPCGMBorderTrack& b = B2[itr];
       float d = CAMath::Max(0.5f, 3.5f * CAMath::Sqrt(b.Cov()[1]));
-      if (CAMath::Abs(b.Par()[4]) >= 20) {
+      if (CAMath::Abs(b.Par()[4]) * Param().par.qptB5Scaler >= 20) {
         d *= 2;
       } else if (d > 3) {
         d = 3;
@@ -907,15 +907,15 @@ GPUd() void GPUTPCGMMerger::MergeBorderTracks<2>(int nBlocks, int nThreads, int
         if (!b1.CheckChi2QPt(b2, factor2k)) {
           CADEBUG2(continue, printf("!QPt\n"));
         }
-        float fys = CAMath::Abs(b1.Par()[4]) < 20 ? factor2ys : (2. * factor2ys);
-        float fzt = CAMath::Abs(b1.Par()[4]) < 20 ? factor2zt : (2. * factor2zt);
+        float fys = CAMath::Abs(b1.Par()[4]) * Param().par.qptB5Scaler < 20 ? factor2ys : (2. * factor2ys);
+        float fzt = CAMath::Abs(b1.Par()[4]) * Param().par.qptB5Scaler < 20 ? factor2zt : (2. * factor2zt);
         if (!b1.CheckChi2YS(b2, fys)) {
           CADEBUG2(continue, printf("!YS\n"));
         }
         if (!b1.CheckChi2ZT(b2, fzt)) {
           CADEBUG2(continue, printf("!ZT\n"));
         }
-        if (CAMath::Abs(b1.Par()[4]) < 20) {
+        if (CAMath::Abs(b1.Par()[4]) * Param().par.qptB5Scaler < 20) {
           if (b2.NClusters() < minNPartHits) {
             CADEBUG2(continue, printf("!NCl2\n"));
           }
@@ -1176,7 +1176,7 @@ GPUd() void GPUTPCGMMerger::ResolveMergeSlices(GPUResolveSharedMemory& smem, int
       GPUTPCGMSliceTrack* track1Base = track1;
       GPUTPCGMSliceTrack* track2Base = track2;
 
-      bool sameSegment = CAMath::Abs(track1->NClusters() > track2->NClusters() ? track1->QPt() : track2->QPt()) < 2 || track1->QPt() * track2->QPt() > 0;
+      bool sameSegment = CAMath::Abs(track1->NClusters() > track2->NClusters() ? track1->QPt() : track2->QPt()) * Param().par.qptB5Scaler < 2 || track1->QPt() * track2->QPt() > 0;
       // GPUInfo("\nMerge %d with %d - same segment %d", itr, itr2, (int) sameSegment);
       // PrintMergeGraph(track1, std::cout);
       // PrintMergeGraph(track2, std::cout);
@@ -1310,7 +1310,7 @@ GPUd() void GPUTPCGMMerger::MergeCEFill(const GPUTPCGMSliceTrack* track, const G
   }
 
 #ifdef GPUCA_MERGER_CE_ROWLIMIT
-  if (CAMath::Abs(track->QPt()) < 0.3 && (cls.row < GPUCA_MERGER_CE_ROWLIMIT || cls.row >= GPUCA_ROW_COUNT - GPUCA_MERGER_CE_ROWLIMIT)) {
+  if (CAMath::Abs(track->QPt()) * Param().par.qptB5Scaler < 0.3 && (cls.row < GPUCA_MERGER_CE_ROWLIMIT || cls.row >= GPUCA_ROW_COUNT - GPUCA_MERGER_CE_ROWLIMIT)) {
     return;
   }
 #endif
@@ -1363,7 +1363,7 @@ GPUd() void GPUTPCGMMerger::MergeCE(int nBlocks, int nThreads, int iBlock, int i
       if (!trk[1]->OK() || trk[1]->CCE()) {
         continue;
       }
-      bool looper = trk[0]->Looper() || trk[1]->Looper() || (trk[0]->GetParam().GetQPt() > 1 && trk[0]->GetParam().GetQPt() * trk[1]->GetParam().GetQPt() < 0);
+      bool looper = trk[0]->Looper() || trk[1]->Looper() || (trk[0]->GetParam().GetQPt() * Param().par.qptB5Scaler > 1 && trk[0]->GetParam().GetQPt() * trk[1]->GetParam().GetQPt() < 0);
       if (!looper && trk[0]->GetParam().GetPar(3) * trk[1]->GetParam().GetPar(3) < 0) {
         continue;
       }
@@ -1603,7 +1603,7 @@ GPUd() void GPUTPCGMMerger::CollectMergedTracks(int nBlocks, int nThreads, int i
       }
       nHits += nTrackHits;
     }
-    if (nHits < GPUCA_TRACKLET_SELECTOR_MIN_HITS(track.QPt())) {
+    if (nHits < GPUCA_TRACKLET_SELECTOR_MIN_HITS_B5(track.QPt() * Param().par.qptB5Scaler)) {
       continue;
     }
 
@@ -2014,7 +2014,7 @@ GPUd() void GPUTPCGMMerger::MergeLoopersInit(int nBlocks, int nThreads, int iBlo
     const auto& trk = mOutputTracks[i];
     const auto& p = trk.GetParam();
     const float qptabs = CAMath::Abs(p.GetQPt());
-    if (trk.NClusters() && qptabs > 5.f && qptabs <= lowPtThresh) {
+    if (trk.NClusters() && qptabs * Param().par.qptB5Scaler > 5.f && qptabs <= lowPtThresh) {
       const int slice = mClusters[trk.FirstClusterRef() + trk.NClusters() - 1].slice;
       const float refz = p.GetZ() + (Param().par.earlyTpcTransform ? p.GetTZOffset() : GetConstantMem()->calibObjects.fastTransform->convVertexTimeToZOffset(slice, p.GetTZOffset(), Param().par.continuousMaxTimeBin)) + (trk.CSide() ? -100 : 100);
       float sinA, cosA;

GPU/GPUTracking/Merger/GPUTPCGMO2Output.cxx

@@ -53,7 +53,7 @@ GPUdii() void GPUTPCGMO2Output::Thread<GPUTPCGMO2Output::prepare>(int nBlocks, i
     if (nCl == 0) {
       continue;
     }
-    if (merger.Param().rec.tpc.dropSecondaryLegsInOutput && nCl + 2 < GPUCA_TRACKLET_SELECTOR_MIN_HITS(tracks[i].GetParam().GetQPt())) { // Give 2 hits tolerance in the primary leg, compared to the full fit of the looper
+    if (merger.Param().rec.tpc.dropSecondaryLegsInOutput && nCl + 2 < GPUCA_TRACKLET_SELECTOR_MIN_HITS_B5(tracks[i].GetParam().GetQPt() * merger.Param().par.qptB5Scaler)) { // Give 2 hits tolerance in the primary leg, compared to the full fit of the looper
       continue;
     }
     unsigned int myId = CAMath::AtomicAdd(&merger.Memory()->nO2Tracks, 1u);

GPU/GPUTracking/Merger/GPUTPCGMTrackParam.cxx

@@ -313,7 +313,7 @@ GPUd() bool GPUTPCGMTrackParam::Fit(GPUTPCGMMerger* GPUrestrict() merger, int iT
         ihitStart = ihit;
         float dy = mP[0] - prop.Model().Y();
         float dz = mP[1] - prop.Model().Z();
-        if (CAMath::Abs(mP[4]) > 10 && --resetT0 <= 0 && CAMath::Abs(mP[2]) < 0.15f && dy * dy + dz * dz > 1) {
+        if (CAMath::Abs(mP[4]) * merger->Param().par.qptB5Scaler > 10 && --resetT0 <= 0 && CAMath::Abs(mP[2]) < 0.15f && dy * dy + dz * dz > 1) {
           CADEBUG(printf("Reinit linearization\n"));
           prop.SetTrack(this, prop.GetAlpha());
         }
@@ -347,7 +347,7 @@ GPUd() bool GPUTPCGMTrackParam::Fit(GPUTPCGMMerger* GPUrestrict() merger, int iT
   }
   ConstrainSinPhi();
 
-  if (!(N + NTolerated >= GPUCA_TRACKLET_SELECTOR_MIN_HITS(mP[4]) && 2 * NTolerated <= CAMath::Max(10, N) && CheckNumericalQuality(covYYUpd))) {
+  if (!(N + NTolerated >= GPUCA_TRACKLET_SELECTOR_MIN_HITS_B5(mP[4] * merger->Param().par.qptB5Scaler) && 2 * NTolerated <= CAMath::Max(10, N) && CheckNumericalQuality(covYYUpd))) {
     return (false); // TODO: NTolerated should never become that large, check what is going wrong!
   }
   // TODO: we have looping tracks here with 0 accepted clusters in the primary leg. In that case we should refit the track using only the primary leg.

GPU/GPUTracking/SliceTracker/GPUTPCTrackerComponent.cxx

@@ -44,7 +44,7 @@ const AliHLTComponentDataType GPUTPCDefinitions::fgkTrackletsDataType = AliHLTCo
 ClassImp(GPUTPCTrackerComponent);
 
 GPUTPCTrackerComponent::GPUTPCTrackerComponent()
-  : fSolenoidBz(0), fMinNTrackClusters(-1), fMinTrackPt(GPUCA_MIN_TRACK_PT_DEFAULT), fClusterZCut(500.), mNeighboursSearchArea(0), fClusterErrorCorrectionY(0), fClusterErrorCorrectionZ(0), fBenchmark("CATracker"), fAllowGPU(0), fGPUHelperThreads(-1), fCPUTrackers(0), fGlobalTracking(0), fGPUDeviceNum(-1), fGPUType("CPU"), fGPUStuckProtection(0), fAsync(0), fSearchWindowDZDR(0.), fRec(0), fChain(0), fAsyncProcessor()
+  : fSolenoidBz(0), fMinNTrackClusters(-1), fMinTrackPt(GPUCA_MIN_TRACK_PTB5_DEFAULT), fClusterZCut(500.), mNeighboursSearchArea(0), fClusterErrorCorrectionY(0), fClusterErrorCorrectionZ(0), fBenchmark("CATracker"), fAllowGPU(0), fGPUHelperThreads(-1), fCPUTrackers(0), fGlobalTracking(0), fGPUDeviceNum(-1), fGPUType("CPU"), fGPUStuckProtection(0), fAsync(0), fSearchWindowDZDR(0.), fRec(0), fChain(0), fAsyncProcessor()
 {
   // see header file for class documentation
   // or
@@ -54,7 +54,7 @@ GPUTPCTrackerComponent::GPUTPCTrackerComponent()
 }
 
 GPUTPCTrackerComponent::GPUTPCTrackerComponent(const GPUTPCTrackerComponent&)
-  : AliHLTProcessor(), fSolenoidBz(0), fMinNTrackClusters(-1), fMinTrackPt(GPUCA_MIN_TRACK_PT_DEFAULT), fClusterZCut(500.), mNeighboursSearchArea(0), fClusterErrorCorrectionY(0), fClusterErrorCorrectionZ(0), fBenchmark("CATracker"), fAllowGPU(0), fGPUHelperThreads(-1), fCPUTrackers(0), fGlobalTracking(0), fGPUDeviceNum(-1), fGPUType("CPU"), fGPUStuckProtection(0), fAsync(0), fSearchWindowDZDR(0.), fRec(0), fChain(0), fAsyncProcessor()
+  : AliHLTProcessor(), fSolenoidBz(0), fMinNTrackClusters(-1), fMinTrackPt(GPUCA_MIN_TRACK_PTB5_DEFAULT), fClusterZCut(500.), mNeighboursSearchArea(0), fClusterErrorCorrectionY(0), fClusterErrorCorrectionZ(0), fBenchmark("CATracker"), fAllowGPU(0), fGPUHelperThreads(-1), fCPUTrackers(0), fGlobalTracking(0), fGPUDeviceNum(-1), fGPUType("CPU"), fGPUStuckProtection(0), fAsync(0), fSearchWindowDZDR(0.), fRec(0), fChain(0), fAsyncProcessor()
 {
   // see header file for class documentation
   HLTFatal("copy constructor untested");
@@ -121,7 +121,7 @@ void GPUTPCTrackerComponent::SetDefaultConfiguration()
 
   fSolenoidBz = -5.00668;
   fMinNTrackClusters = -1;
-  fMinTrackPt = GPUCA_MIN_TRACK_PT_DEFAULT;
+  fMinTrackPt = GPUCA_MIN_TRACK_PTB5_DEFAULT;
   fClusterZCut = 500.;
   mNeighboursSearchArea = 0;
   fClusterErrorCorrectionY = 0;

GPU/GPUTracking/SliceTracker/GPUTPCTrackletConstructor.cxx

@@ -58,7 +58,7 @@ MEM_CLASS_PRE23()
 GPUd() void GPUTPCTrackletConstructor::StoreTracklet(int /*nBlocks*/, int /*nThreads*/, int /*iBlock*/, int /*iThread*/, GPUsharedref() MEM_LOCAL(GPUSharedMemory) & s, GPUTPCThreadMemory& GPUrestrict() r, GPUconstantref() MEM_LG2(GPUTPCTracker) & GPUrestrict() tracker, MEM_LG3(GPUTPCTrackParam) & GPUrestrict() tParam, calink* rowHits)
 {
   // reconstruction of tracklets, tracklet store step
-  if (r.mNHits == 0 || (r.mNHits < GPUCA_TRACKLET_SELECTOR_MIN_HITS(tParam.QPt()) || !CheckCov(tParam) || CAMath::Abs(tParam.GetQPt()) > tracker.Param().rec.maxTrackQPt)) {
+  if (r.mNHits == 0 || (r.mNHits < GPUCA_TRACKLET_SELECTOR_MIN_HITS_B5(tParam.QPt() * tracker.Param().par.qptB5Scaler) || !CheckCov(tParam) || CAMath::Abs(tParam.GetQPt()) > tracker.Param().rec.maxTrackQPt)) {
     return;
   }
 

GPU/GPUTracking/SliceTracker/GPUTPCTrackletSelector.cxx

@@ -58,7 +58,7 @@ GPUdii() void GPUTPCTrackletSelector::Thread<0>(int nBlocks, int nThreads, int i
     int gap = 0;
     int nShared = 0;
     int nHits = 0;
-    const int minHits = tracker.Param().rec.tpc.minNTrackClusters == -1 ? GPUCA_TRACKLET_SELECTOR_MIN_HITS(tracklet.Param().QPt()) : tracker.Param().rec.tpc.minNTrackClusters;
+    const int minHits = tracker.Param().rec.tpc.minNTrackClusters == -1 ? GPUCA_TRACKLET_SELECTOR_MIN_HITS_B5(tracklet.Param().QPt() * tracker.Param().par.qptB5Scaler) : tracker.Param().rec.tpc.minNTrackClusters;
 
     GPUCA_UNROLL(, U(1))
     for (irow = firstRow; irow <= lastRow && lastRow - irow + nHits >= minHits; irow++) {

GPU/GPUTracking/oldFiles/GPUTPCGMOfflineFitter.cxx

@@ -260,7 +260,7 @@ bool GPUTPCGMOfflineFitter::FitOffline(const GPUTPCGMPolynomialField* field, GPU
 
   t.ConstrainSinPhi();
 
-  bool ok1 = N >= GPUCA_TRACKLET_SELECTOR_MIN_HITS(t.GetQPt()) && t.CheckNumericalQuality(covYYUpd);
+  bool ok1 = N >= GPUCA_TRACKLET_SELECTOR_MIN_HITS_B5(t.GetQPt()) && t.CheckNumericalQuality(covYYUpd);
   if (!ok1) {
     return (false);
   }