Add new MC process function for mixing

Author: skundu692

PWGLF/Tasks/Strangeness/lambdaspincorrderived.cxx

@@ -1191,44 +1191,26 @@ struct lambdaspincorrderived {
         if (ptB < 0 || etaB < 0 || phiB < 0 || mB < 0)
           continue;
 
+        // Collect partners from nominal key, plus wrapped neighbor only for φ-edge bins
         std::vector<MatchRef> matches;
-        const int maxKeep = maxMatchesPerPair.value; // default 25
-        matches.reserve(std::max(64, maxKeep > 0 ? maxKeep : 64));
-
+        matches.reserve(128); // or keep binVec.size() if you prefer
         const int64_t curColIdx = static_cast<int64_t>(collision1.index());
-        std::unordered_set<int64_t> seenRow;
-        seenRow.reserve(static_cast<size_t>(std::max(256, 4 * (maxKeep > 0 ? maxKeep : 64))));
-
-        auto collectFrom = [&](int ptUse, int etaUse, int phiUse) {
-          if (maxKeep > 0 && static_cast<int>(matches.size()) >= maxKeep) {
-            return; // early stop
-          }
 
-          const size_t keyUse = linearKey(colBin, status, ptUse, etaUse, phiUse, mB,
+        auto collectFrom = [&](int phiBinUse) {
+          const size_t keyUse = linearKey(colBin, status, ptB, etaB, phiBinUse, mB,
                                           nStat, nPt, nEta, nPhi, nM);
           auto const& vec = buffer[keyUse];
-
           for (const auto& bc : vec) {
-            if (maxKeep > 0 && static_cast<int>(matches.size()) >= maxKeep) {
-              break;
-            }
             if (bc.collisionIdx == curColIdx) {
               continue; // must be from different event
             }
-
-            // dedupe first
-            if (!seenRow.insert(bc.rowIndex).second) {
-              continue;
-            }
-
             auto tX = V0s.iteratorAt(static_cast<uint64_t>(bc.rowIndex));
             if (!selectionV0(tX)) {
               continue;
             }
             if (!checkKinematics(t1, tX)) {
               continue;
             }
-
             matches.push_back(MatchRef{bc.collisionIdx, bc.rowIndex});
           }
         };