[PWGCF] fixing wrong indeices (#13606)

Co-authored-by: ALICE Action Bot <alibuild@cern.ch>

Author: jikim1290

PWGCF/JCorran/Tasks/jEPFlowAnalysis.cxx

@@ -189,11 +189,14 @@ struct jEPFlowAnalysis {
       }
     }
 
+    if (coll.qvecAmp()[detId] < 1e-5 || coll.qvecAmp()[refAId] < 1e-5 || coll.qvecAmp()[refBId] < 1e-5)
+      return;
+
     for (int i = 0; i < cfgnMode; i++) {       // loop over different harmonic orders
       harmInd = cfgnTotalSystem * 4 * (i) + 3; // harmonic index to access corresponding Q-vector as all Q-vectors are in same vector
-      eps[0] = helperEP.GetEventPlane(coll.qvecRe()[detId + harmInd], coll.qvecIm()[detId + harmInd], i + 2);
-      eps[1] = helperEP.GetEventPlane(coll.qvecRe()[refAId + harmInd], coll.qvecIm()[refAId + harmInd], i + 2);
-      eps[2] = helperEP.GetEventPlane(coll.qvecRe()[refBId + harmInd], coll.qvecIm()[refBId + harmInd], i + 2);
+      eps[0] = helperEP.GetEventPlane(coll.qvecRe()[4 * detId + harmInd], coll.qvecIm()[4 * detId + harmInd], i + 2);
+      eps[1] = helperEP.GetEventPlane(coll.qvecRe()[4 * refAId + harmInd], coll.qvecIm()[4 * refAId + harmInd], i + 2);
+      eps[2] = helperEP.GetEventPlane(coll.qvecRe()[4 * refBId + harmInd], coll.qvecIm()[4 * refBId + harmInd], i + 2);
 
       auto deltapsiDet = 0.0;
       auto deltapsiRefA = 0.0;
@@ -222,7 +225,7 @@ struct jEPFlowAnalysis {
       }
 
       if (cfgSPmethod)
-        weight *= std::sqrt(std::pow(coll.qvecRe()[detId + harmInd], 2) + std::pow(coll.qvecIm()[detId + harmInd], 2));
+        weight *= std::sqrt(std::pow(coll.qvecRe()[4 * detId + harmInd], 2) + std::pow(coll.qvecIm()[4 * detId + harmInd], 2));
 
       float resNumA = helperEP.GetResolution(eps[0], eps[1], i + 2);
       float resNumB = helperEP.GetResolution(eps[0], eps[2], i + 2);