GPU: Add looperFollowMode option

Author: davidrohr

GPU/GPUTracking/Definitions/GPUSettingsList.h

@@ -147,6 +147,7 @@ AddOptionRTC(dEdxTruncLow, uint8_t, 2, "", 0, "Low truncation threshold, fractio
 AddOptionRTC(dEdxTruncHigh, uint8_t, 77, "", 0, "High truncation threshold, fraction of 128")
 AddOptionRTC(extrapolationTracking, int8_t, 1, "", 0, "Enable Extrapolation Tracking (prolong tracks to adjacent sectors to find short segments)")
 AddOptionRTC(disableRefitAttachment, uint8_t, 0, "", 0, "Bitmask to disable certain attachment steps during refit (1: attachment, 2: propagation, 4: loop following)")
+AddOptionRTC(looperFollowMode, uint8_t, 1, "", 0, "0 = simple, 1 = advances, for disabling use disableRefitAttachment = 4")
 AddOptionRTC(rejectionStrategy, uint8_t, o2::gpu::GPUSettings::RejectionStrategyA, "", 0, "Enable rejection of TPC clusters for compression (0 = no, 1 = strategy A, 2 = strategy B)")
 AddOptionRTC(mergeLoopersAfterburner, uint8_t, 1, "", 0, "Run afterburner for additional looper merging")
 AddOptionRTC(compressionTypeMask, uint8_t, o2::gpu::GPUSettings::CompressionFull, "", 0, "TPC Compression mode bits (1=truncate charge/width LSB, 2=differences, 4=track-model)")

GPU/GPUTracking/Merger/GPUTPCGMTrackParam.cxx

@@ -795,10 +795,10 @@ GPUdii() void GPUTPCGMTrackParam::PropagateLooper(const GPUTPCGMMerger& GPUrestr
 
   GPUTPCGMLoopData& data = merger.LoopData()[loopIdx];
   prop.SetTrack(&data.param, data.alpha);
-  if (false) {
-    data.param.AttachClustersLooper(merger, data.sector, data.row, data.track, data.outwards, prop);
-  } else {
+  if (merger.Param().rec.tpc.looperFollowMode == 1) {
     data.param.AttachClustersLooperFollow(merger, prop, data.sector, data.row, data.track, data.outwards);
+  } else {
+    data.param.AttachClustersLooper(merger, data.sector, data.row, data.track, data.outwards, prop);
   }
 }