GPU TPC: Better formula for cluster weights

davidrohr · davidrohr · commit 0cb5fc5c8787 · 2025-09-11T08:23:54.000+02:00
diff --git a/GPU/GPUTracking/SectorTracker/GPUTPCTracker.h b/GPU/GPUTracking/SectorTracker/GPUTPCTracker.h
@@ -160,13 +160,11 @@ class GPUTPCTracker : public GPUProcessor
    */
   GPUdi() static int32_t CalculateHitWeight(int32_t NHits, float chi2)
   {
-    const float chi2_suppress = 6.f;
-    float weight = (((float)NHits * (chi2_suppress - chi2 / 500.f)) * (1e9f / chi2_suppress / 160.f));
+    float weight = NHits * (NHits * 2 - 5) * 128 / chi2; // TODO: Add QPt to this formula
     if (weight < 0.f || weight > 2e9f) {
       return 0;
     }
     return ((int32_t)weight);
-    // return( (NHits << 16) + num);
   }
   GPUd() void MaximizeHitWeight(const GPUTPCRow& row, int32_t hitIndex, int32_t weight) { mData.MaximizeHitWeight(row, hitIndex, weight); }
   GPUd() void SetHitWeight(const GPUTPCRow& row, int32_t hitIndex, int32_t weight) { mData.SetHitWeight(row, hitIndex, weight); }

Original file line number	Diff line number	Diff line change
`@@ -160,13 +160,11 @@ class GPUTPCTracker : public GPUProcessor`
`160`	`160`	`*/`
`161`	`161`	`GPUdi() static int32_t CalculateHitWeight(int32_t NHits, float chi2)`
`162`	`162`	`{`
`163`		`- const float chi2_suppress = 6.f;`
`164`		`- float weight = (((float)NHits * (chi2_suppress - chi2 / 500.f)) * (1e9f / chi2_suppress / 160.f));`
	`163`	`+ float weight = NHits * (NHits * 2 - 5) * 128 / chi2; // TODO: Add QPt to this formula`
`165`	`164`	`if (weight < 0.f \|\| weight > 2e9f) {`
`166`	`165`	`return 0;`
`167`	`166`	`}`
`168`	`167`	`return ((int32_t)weight);`
`169`		`- // return( (NHits << 16) + num);`
`170`	`168`	`}`
`171`	`169`	`GPUd() void MaximizeHitWeight(const GPUTPCRow& row, int32_t hitIndex, int32_t weight) { mData.MaximizeHitWeight(row, hitIndex, weight); }`
`172`	`170`	`GPUd() void SetHitWeight(const GPUTPCRow& row, int32_t hitIndex, int32_t weight) { mData.SetHitWeight(row, hitIndex, weight); }`