clean up intersection code

CQCL · Dec 4, 2023 · ae92c47 · ae92c47
1 parent a53679b
commit ae92c47
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Showing 2 changed files with 9 additions and 12 deletions.
diff --git a/tket/src/Characterisation/Cycles.cpp b/tket/src/Characterisation/Cycles.cpp
@@ -170,16 +170,15 @@ std::pair<unsigned, std::set<unsigned>> CycleFinder::make_cycle(
         if (std::find(
                 history_uids.begin(), history_uids.end(), not_present_uid) !=
             history_uids.end()) {
-          // => the not present uid is in this cycle
-          // now we check the overlap
-          //
-          for (const UnitID& a :
-               this->cycle_history.history[candidate_cycle_key]) {
-            for (const UnitID& b : history_uids) {
-              if (a == b) {
-                not_mergeable_keys.insert(candidate_cycle_key);
-              }
-            }
+          std::vector<UnitID> intersection;
+          std::vector<UnitID> candidates =
+              cycle_history.history[candidate_cycle_key];
+          std::set_intersection(
+              candidates.begin(), candidates.end(), history_uids.begin(),
+              history_uids.end(), std::back_inserter(intersection));
+          if (!intersection.empty()) {
+            not_mergeable_keys.insert(candidate_cycle_key);
+            break;
           }
         }
       }

diff --git a/tket/src/Characterisation/FrameRandomisation.cpp b/tket/src/Characterisation/FrameRandomisation.cpp
@@ -45,8 +45,6 @@ std::string FrameRandomisation::to_string() const {
 // Wires Identity gates into each cycle edge. Identity gates then relabelled
 // with Ops from OpTypeSet to create instances of Frame Randomisation
 void add_noop_frames(std::vector<Cycle>& cycles, Circuit& circ) {
-  IndexMap imap = circ.index_map();
-
   std::map<Edge, Edge> replacement_rewiring_edges;
   for (Cycle& full_cycle : cycles) {
     std::vector<edge_pair_t> cycle = full_cycle.boundary_edges_;