GPU TPC: Require minimum NDF for mergerInterpolateRejectAlsoOnCurrentPosition to avoid killing some tracks when some first clusters are bad

Author: davidrohr

GPU/GPUTracking/Definitions/GPUSettingsList.h

@@ -148,7 +148,7 @@ AddOptionRTC(sigBitsCharge, uint8_t, 4, "", 0, "Number of significant bits for T
 AddOptionRTC(sigBitsWidth, uint8_t, 3, "", 0, "Number of significant bits for TPC cluster width in compression mode 1")
 AddOptionRTC(dropLoopers, uint8_t, 0, "", 0, "Drop looping tracks starting from second loop")
 AddOptionRTC(mergerInterpolateErrors, uint8_t, 1, "", 0, "Use interpolation instead of extrapolation for chi2 based cluster rejection")
-AddOptionRTC(mergerInterpolateRejectAlsoOnCurrentPosition, uint8_t, 1, "", 0, "When using mergerInterpolateErrors, reject based on chi2 twice computed with interpolated and current track position")
+AddOptionRTC(mergerInterpolateRejectAlsoOnCurrentPosition, uint8_t, 1, "", 0, "When using mergerInterpolateErrors, reject based on chi2 twice computed with interpolated and current track position starting from NDF > 5")
 AddOptionRTC(mergeCE, uint8_t, 1, "", 0, "Merge tracks accross the central electrode")
 AddOptionRTC(retryRefit, int8_t, 1, "", 0, "Retry refit with seeding errors and without cluster rejection when fit fails (=2 means retry in same kernel, =1 for separate kernel")
 AddOptionRTC(enablePID, int8_t, 1, "", 0, "Enable PID response")

GPU/GPUTracking/Merger/GPUTPCGMPropagator.cxx

@@ -643,7 +643,7 @@ GPUd() int32_t GPUTPCGMPropagator::Update(float posY, float posZ, int32_t iRow,
     return 0;
   }
 
-  return Update(posY, posZ, clusterState, rejectChi2 == rejectDirect || (param.rec.tpc.mergerInterpolateRejectAlsoOnCurrentPosition && rejectChi2 == rejectInterReject), err2Y, err2Z, &param);
+  return Update(posY, posZ, clusterState, rejectChi2 == rejectDirect || (param.rec.tpc.mergerInterpolateRejectAlsoOnCurrentPosition && rejectChi2 == rejectInterReject && mT->GetNDF() > 5 ), err2Y, err2Z, &param);
 }
 
 GPUd() int32_t GPUTPCGMPropagator::InterpolateReject(const GPUParam& GPUrestrict() param, float posY, float posZ, int16_t clusterState, int8_t rejectChi2, gputpcgmmergertypes::InterpolationErrorHit* inter, float err2Y, float err2Z)