Issue1075

src/search/landmarks/landmark_heuristic.cc

@@ -13,28 +13,6 @@
 using namespace std;
 
 namespace landmarks {
-static bool landmark_is_interesting(
-    const State &state, ConstBitsetView &past,
-    const landmarks::LandmarkNode &lm_node, bool all_lms_reached) {
-    /*
-      We consider a landmark interesting in two (exclusive) cases:
-      (1) If all landmarks are reached and the landmark must hold in the goal
-          but does not hold in the current state.
-      (2) If it has not been reached before and all its parents are reached.
-    */
-
-    if (all_lms_reached) {
-        const Landmark &landmark = lm_node.get_landmark();
-        return landmark.is_true_in_goal && !landmark.is_true_in_state(state);
-    } else {
-        return !past.test(lm_node.get_id()) &&
-               all_of(lm_node.parents.begin(), lm_node.parents.end(),
-                      [&](const pair<LandmarkNode *, EdgeType> parent) {
-                          return past.test(parent.first->get_id());
-                      });
-    }
-}
-
 LandmarkHeuristic::LandmarkHeuristic(
     const plugins::Options &opts)
     : Heuristic(opts),
@@ -137,30 +115,16 @@ void LandmarkHeuristic::compute_landmark_graph(const plugins::Options &opts) {
 }
 
 void LandmarkHeuristic::generate_preferred_operators(
-    const State &state, ConstBitsetView &past) {
+    const State &state, ConstBitsetView &future) {
     /*
-      Find operators that achieve landmark leaves. If a simple landmark can be
-      achieved, prefer only operators that achieve simple landmarks. Otherwise,
-      prefer operators that achieve disjunctive landmarks, or don't prefer any
-      operators if no such landmarks exist at all.
-
+      Find operators that achieve future landmarks.
       TODO: Conjunctive landmarks are ignored in *lm_graph->get_node(...)*, so
        they are ignored when computing preferred operators. We consider this
        a bug and want to fix it in issue1072.
     */
     assert(successor_generator);
     vector<OperatorID> applicable_operators;
     successor_generator->generate_applicable_ops(state, applicable_operators);
-    vector<OperatorID> preferred_operators_simple;
-    vector<OperatorID> preferred_operators_disjunctive;
-
-    bool all_landmarks_past = true;
-    for (int i = 0; i < past.size(); ++i) {
-        if (!past.test(i)) {
-            all_landmarks_past = false;
-            break;
-        }
-    }
 
     for (OperatorID op_id : applicable_operators) {
         OperatorProxy op = task_proxy.get_operators()[op_id];
@@ -170,27 +134,11 @@ void LandmarkHeuristic::generate_preferred_operators(
                 continue;
             FactProxy fact_proxy = effect.get_fact();
             LandmarkNode *lm_node = lm_graph->get_node(fact_proxy.get_pair());
-            if (lm_node && landmark_is_interesting(
-                    state, past, *lm_node, all_landmarks_past)) {
-                if (lm_node->get_landmark().disjunctive) {
-                    preferred_operators_disjunctive.push_back(op_id);
-                } else {
-                    preferred_operators_simple.push_back(op_id);
-                }
+            if (lm_node && future.test(lm_node->get_id())) {
+                set_preferred(op);
             }
         }
     }
-
-    OperatorsProxy operators = task_proxy.get_operators();
-    if (preferred_operators_simple.empty()) {
-        for (OperatorID op_id : preferred_operators_disjunctive) {
-            set_preferred(operators[op_id]);
-        }
-    } else {
-        for (OperatorID op_id : preferred_operators_simple) {
-            set_preferred(operators[op_id]);
-        }
-    }
 }
 
 int LandmarkHeuristic::compute_heuristic(const State &ancestor_state) {
@@ -220,10 +168,10 @@ int LandmarkHeuristic::compute_heuristic(const State &ancestor_state) {
     }
     int h = get_heuristic_value(ancestor_state);
     if (use_preferred_operators) {
-        ConstBitsetView past =
-            lm_status_manager->get_past_landmarks(ancestor_state);
+        ConstBitsetView future =
+            lm_status_manager->get_future_landmarks(ancestor_state);
         State state = convert_ancestor_state(ancestor_state);
-        generate_preferred_operators(state, past);
+        generate_preferred_operators(state, future);
     }
     return h;
 }

src/search/landmarks/landmark_heuristic.h

@@ -37,7 +37,7 @@ class LandmarkHeuristic : public Heuristic {
     virtual int get_heuristic_value(const State &ancestor_state) = 0;
 
     void generate_preferred_operators(
-        const State &state, ConstBitsetView &past);
+        const State &state, ConstBitsetView &future);
     virtual int compute_heuristic(const State &ancestor_state) override;
 public:
     explicit LandmarkHeuristic(const plugins::Options &opts);