GPU TPC: Fix deterministic mode for TPC cluster compression / decompression / looper merging afterburner

Author: davidrohr

GPU/GPUTracking/Base/cuda/GPUReconstructionCUDAKernelsSpecialize.inc

@@ -82,14 +82,14 @@ struct GPUTPCGMMergerSortTracksQPt_comp {
 struct GPUTPCGMMergerMergeLoopers_comp {
   GPUd() bool operator()(const MergeLooperParam& a, const MergeLooperParam& b)
   {
-    return CAMath::Abs(a.refz) < CAMath::Abs(b.refz);
+    return GPUCA_DETERMINISTIC_CODE(CAMath::Abs(a.refz) != CAMath::Abs(b.refz) ? CAMath::Abs(a.refz) < CAMath::Abs(b.refz) : a.id < b.id, CAMath::Abs(a.refz) < CAMath::Abs(b.refz));
   }
 };
 
 struct GPUTPCGMO2OutputSort_comp {
   GPUd() bool operator()(const GPUTPCGMMerger::tmpSort& a, const GPUTPCGMMerger::tmpSort& b)
   {
-    return (a.y > b.y);
+    return GPUCA_DETERMINISTIC_CODE(a.y != b.y ? a.y > b.y : a.x > b.x, a.y > b.y);
   }
 };
 

GPU/GPUTracking/Merger/GPUTPCGMMerger.cxx

@@ -1948,7 +1948,7 @@ GPUd() void GPUTPCGMMerger::MergeLoopersSort(int32_t nBlocks, int32_t nThreads,
   if (iThread || iBlock) {
     return;
   }
-  auto comp = [](const MergeLooperParam& a, const MergeLooperParam& b) { return CAMath::Abs(a.refz) < CAMath::Abs(b.refz); };
+  auto comp = [](const MergeLooperParam& a, const MergeLooperParam& b) { return GPUCA_DETERMINISTIC_CODE(CAMath::Abs(a.refz) != CAMath::Abs(b.refz) ? CAMath::Abs(a.refz) < CAMath::Abs(b.refz) : a.id < b.id, CAMath::Abs(a.refz) < CAMath::Abs(b.refz)); };
   GPUCommonAlgorithm::sortDeviceDynamic(mLooperCandidates, mLooperCandidates + mMemory->nLooperMatchCandidates, comp);
 #endif
 }

GPU/GPUTracking/Merger/GPUTPCGMO2Output.cxx

@@ -88,7 +88,7 @@ GPUdii() void GPUTPCGMO2Output::Thread<GPUTPCGMO2Output::sort>(int32_t nBlocks,
     return;
   }
   GPUTPCGMMerger::tmpSort* GPUrestrict() trackSort = merger.TrackSortO2();
-  auto comp = [](const auto& a, const auto& b) { return (a.y > b.y); };
+  auto comp = [](const auto& a, const auto& b) { return GPUCA_DETERMINISTIC_CODE(a.y != b.y ? a.y > b.y : a.x > b.x, a.y > b.y); };
   GPUCommonAlgorithm::sortDeviceDynamic(trackSort, trackSort + merger.Memory()->nO2Tracks, comp);
 #endif
 }