Preserve reward models in graph-preserving bisim

src/storm/api/bisimulation.h

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <any>
 #include "storm/models/sparse/Ctmc.h"
 #include "storm/models/sparse/Dtmc.h"
 #include "storm/models/sparse/Mdp.h"
@@ -24,8 +25,16 @@ std::shared_ptr<ModelType> performDeterministicSparseBisimulationMinimization(st
     if (!formulas.empty() && graphPreserving) {
         options = typename storm::storage::DeterministicModelBisimulationDecomposition<ModelType>::Options(*model, formulas);
     }
+    // If we cannot use formula-based decomposition because of
+    // non-graph-preserving regions but there are reward models, we need to
+    // preserve those
+    if (!graphPreserving && std::any_of(formulas.begin(), formulas.end(), [](auto const& formula) {
+            return formula->getReferencedRewardModels().size() > 0;
+        })) {
+        options.setKeepRewards(true);
+    }
     options.setType(type);
-
+    
     storm::storage::DeterministicModelBisimulationDecomposition<ModelType> bisimulationDecomposition(*model, options);
     bisimulationDecomposition.computeBisimulationDecomposition();
     return bisimulationDecomposition.getQuotient();
@@ -39,6 +48,14 @@ std::shared_ptr<ModelType> performNondeterministicSparseBisimulationMinimization
     if (!formulas.empty() && graphPreserving) {
         options = typename storm::storage::NondeterministicModelBisimulationDecomposition<ModelType>::Options(*model, formulas);
     }
+    // If we cannot use formula-based decomposition because of
+    // non-graph-preserving regions but there are reward models, we need to
+    // preserve those
+    if (!graphPreserving && std::any_of(formulas.begin(), formulas.end(), [](auto const& formula) {
+            return formula->getReferencedRewardModels().size() > 0;
+        })) {
+        options.setKeepRewards(true);
+    }
     options.setType(type);
 
     storm::storage::NondeterministicModelBisimulationDecomposition<ModelType> bisimulationDecomposition(*model, options);

src/storm/storage/bisimulation/BisimulationDecomposition.h

@@ -103,6 +103,10 @@ class BisimulationDecomposition : public Decomposition<StateBlock> {
             return this->keepRewards;
         }
 
+        void setKeepRewards(bool keepRewards) {
+            this->keepRewards = keepRewards;
+        }
+
         bool isOptimizationDirectionSet() const {
             return static_cast<bool>(optimalityType);
         }