added a few virtual destructors to prevent memory leaks.

src/storm/modelchecker/multiobjective/pcaa/SparseMaPcaaWeightVectorChecker.h

@@ -31,6 +31,8 @@ namespace storm {
                                                           storm::storage::BitVector const& ecActions,
                                                           storm::storage::BitVector const& possiblyRecurrentStates);
                 
+                virtual ~SparseMaPcaaWeightVectorChecker() = default;
+
             private:
                 
                 /*

src/storm/modelchecker/multiobjective/pcaa/SparseMdpPcaaWeightVectorChecker.h

@@ -26,6 +26,8 @@ namespace storm {
                                                  storm::storage::BitVector const& ecActions,
                                                  storm::storage::BitVector const& possiblyRecurrentStates);
 
+                virtual ~SparseMdpPcaaWeightVectorChecker() = default;
+
             private:
                 
                 /*!

src/storm/modelchecker/multiobjective/pcaa/SparsePcaaAchievabilityQuery.h

@@ -25,6 +25,7 @@ namespace storm {
                  */
                 SparsePcaaAchievabilityQuery(SparsePcaaPreprocessorReturnType<SparseModelType>& preprocessorResult);
                 
+                virtual ~SparsePcaaAchievabilityQuery() = default;
 
                 /*
                  * Invokes the computation and retrieves the result

src/storm/modelchecker/multiobjective/pcaa/SparsePcaaParetoQuery.h

@@ -25,6 +25,8 @@ namespace storm {
                  */
                 SparsePcaaParetoQuery(SparsePcaaPreprocessorReturnType<SparseModelType>& preprocessorResult);
                 
+                virtual ~SparsePcaaParetoQuery() = default;
+
                 
                 /*
                  * Invokes the computation and retrieves the result

src/storm/modelchecker/multiobjective/pcaa/SparsePcaaQuantitativeQuery.h

@@ -25,6 +25,7 @@ namespace storm {
                  */
                 SparsePcaaQuantitativeQuery(SparsePcaaPreprocessorReturnType<SparseModelType>& preprocessorResult);
                 
+                virtual ~SparsePcaaQuantitativeQuery() = default;
 
                 /*
                  * Invokes the computation and retrieves the result

src/storm/modelchecker/multiobjective/pcaa/SparsePcaaQuery.h

@@ -22,6 +22,8 @@ namespace storm {
                 typedef std::vector<GeometryValueType> Point;
                 typedef std::vector<GeometryValueType> WeightVector;
                 
+                virtual ~SparsePcaaQuery() = default;
+                
                 /*
                  * Invokes the computation and retrieves the result
                  */

src/storm/modelchecker/multiobjective/pcaa/SparsePcaaWeightVectorChecker.h

@@ -40,6 +40,8 @@ namespace storm {
                                                         storm::storage::BitVector const& ecActions,
                                                         storm::storage::BitVector const& possiblyRecurrentStates);
                 
+                virtual ~SparsePcaaWeightVectorChecker() = default;
+                
                 /*!
                  * - computes the maximal expected reward w.r.t. the weighted sum of the rewards of the individual objectives
                  * - extracts the scheduler that induces this maximum