[issue1091] Change landmark cost partitioning option from bool to enum.

Users of the landmark cost partitioning heuristic must specify which cost
partitioning strategy to use. There are two strategies available right now,
namely uniform or optimal cost partitioning. Previously, the command line option
to choose between them was a boolean "optimal=(false|true)". This changed to an
enum option "cost_partitioning=(uniform|optimal)" to prepare for more choices to
be implemented in the future.

src/search/landmarks/landmark_cost_partitioning_heuristic.cc

@@ -17,7 +17,8 @@ using namespace std;
 namespace landmarks {
 LandmarkCostPartitioningHeuristic::LandmarkCostPartitioningHeuristic(
     const plugins::Options &opts)
-    : LandmarkHeuristic(opts) {
+    : LandmarkHeuristic(opts),
+      cost_partitioning_strategy(opts.get<CostPartitioningStrategy>("cost_partitioning")) {
     if (log.is_at_least_normal()) {
         log << "Initializing landmark cost partitioning heuristic..." << endl;
     }
@@ -46,16 +47,18 @@ void LandmarkCostPartitioningHeuristic::check_unsupported_features(
 
 void LandmarkCostPartitioningHeuristic::set_cost_assignment(
     const plugins::Options &opts) {
-    if (opts.get<bool>("optimal")) {
+    if (cost_partitioning_strategy == CostPartitioningStrategy::OPTIMAL) {
         lm_cost_assignment =
             utils::make_unique_ptr<LandmarkEfficientOptimalSharedCostAssignment>(
                 task_properties::get_operator_costs(task_proxy),
                 *lm_graph, opts.get<lp::LPSolverType>("lpsolver"));
-    } else {
+    } else if (cost_partitioning_strategy == CostPartitioningStrategy::UNIFORM) {
         lm_cost_assignment =
             utils::make_unique_ptr<LandmarkUniformSharedCostAssignment>(
                 task_properties::get_operator_costs(task_proxy),
                 *lm_graph, opts.get<bool>("alm"));
+    } else {
+        ABORT("Unknown cost partitioning strategy");
     }
 }
 
@@ -104,10 +107,10 @@ class LandmarkCostPartitioningHeuristicFeature : public plugins::TypedFeature<Ev
                 "2010"));
 
         LandmarkHeuristic::add_options_to_feature(*this);
-        add_option<bool>(
-            "optimal",
-            "use optimal (LP-based) cost sharing",
-            "false");
+        add_option<CostPartitioningStrategy>(
+            "cost_partitioning",
+            "strategy for partitioning operator costs among landmarks",
+            "uniform");
         add_option<bool>("alm", "use action landmarks", "true");
         lp::add_lp_solver_option_to_feature(*this);
 
@@ -127,7 +130,7 @@ class LandmarkCostPartitioningHeuristicFeature : public plugins::TypedFeature<Ev
             "which point the above inequality might not hold anymore.");
         document_note(
             "Optimal Cost Partitioning",
-            "To use ``optimal=true``, you must build the planner with LP "
+            "To use ``cost_partitioning=optimal``, you must build the planner with LP "
             "support. See LPBuildInstructions.");
         document_note(
             "Preferred operators",
@@ -151,4 +154,12 @@ class LandmarkCostPartitioningHeuristicFeature : public plugins::TypedFeature<Ev
 };
 
 static plugins::FeaturePlugin<LandmarkCostPartitioningHeuristicFeature> _plugin;
+
+static plugins::TypedEnumPlugin<CostPartitioningStrategy> _enum_plugin({
+        {"optimal",
+         "use optimal (LP-based) cost partitioning"},
+        {"uniform",
+         "partition operator costs uniformly among all landmarks "
+         "achieved by that operator"},
+    });
 }

src/search/landmarks/landmark_cost_partitioning_heuristic.h

@@ -6,7 +6,13 @@
 namespace landmarks {
 class LandmarkCostAssignment;
 
+enum class CostPartitioningStrategy {
+    OPTIMAL,
+    UNIFORM,
+};
+
 class LandmarkCostPartitioningHeuristic : public LandmarkHeuristic {
+    const CostPartitioningStrategy cost_partitioning_strategy;
     std::unique_ptr<LandmarkCostAssignment> lm_cost_assignment;
 
     void check_unsupported_features(const plugins::Options &opts);