Add message if nothing about monotonicity is known

src/storm-pars/analysis/MonotonicityChecker.cpp

@@ -68,15 +68,19 @@ namespace storm {
         template <typename ValueType>
         std::map<storm::analysis::Lattice*, std::map<carl::Variable, std::pair<bool, bool>>> MonotonicityChecker<ValueType>::checkMonotonicity(std::map<storm::analysis::Lattice*, std::vector<std::shared_ptr<storm::expressions::BinaryRelationExpression>>> map, storm::storage::SparseMatrix<ValueType> matrix) {
             storm::utility::Stopwatch finalCheckWatch(true);
+            std::map<storm::analysis::Lattice *, std::map<carl::Variable, std::pair<bool, bool>>> result;
             
+            if (map.size() == 0) {
+                STORM_PRINT(std::endl << "Do not know about monotonicity" << std::endl);
+            } else {
                 auto i = 0;
-            std::map<storm::analysis::Lattice*, std::map<carl::Variable, std::pair<bool, bool>>> result;
+
                 for (auto itr = map.begin(); i < map.size() && itr != map.end(); ++itr) {
                     auto lattice = itr->first;
                     auto assumptions = itr->second;
                     std::ofstream myfile;
                     std::string filename = "lattice" + std::to_string(i) + ".dot";
-                myfile.open (filename);
+                    myfile.open(filename);
                     lattice->toDotFile(myfile);
                     myfile.close();
 
@@ -99,24 +103,28 @@ namespace storm {
                         STORM_PRINT(std::endl);
                     }
 
-                std::map<carl::Variable, std::pair<bool, bool>> varsMonotone = analyseMonotonicity(i, lattice, matrix);
+                    std::map<carl::Variable, std::pair<bool, bool>> varsMonotone = analyseMonotonicity(i, lattice,
+                                                                                                       matrix);
                     if (varsMonotone.size() == 0) {
                         STORM_PRINT("Result is constant" << std::endl);
                     } else {
                         for (auto itr2 = varsMonotone.begin(); itr2 != varsMonotone.end(); ++itr2) {
                             if (resultCheckOnSamples.find(itr2->first) != resultCheckOnSamples.end() &&
-                            (!resultCheckOnSamples[itr2->first].first && !resultCheckOnSamples[itr2->first].second)) {
+                                (!resultCheckOnSamples[itr2->first].first &&
+                                 !resultCheckOnSamples[itr2->first].second)) {
                                 STORM_PRINT("  - Not monotone in: " << itr2->first << std::endl);
                             } else {
                                 if (itr2->second.first) {
                                     STORM_PRINT("  - Monotone increasing in: " << itr2->first << std::endl);
                                 } else {
-                                STORM_PRINT("  - Do not know if monotone increasing in: " << itr2->first << std::endl);
+                                    STORM_PRINT(
+                                            "  - Do not know if monotone increasing in: " << itr2->first << std::endl);
                                 }
                                 if (itr2->second.second) {
                                     STORM_PRINT("  - Monotone decreasing in: " << itr2->first << std::endl);
                                 } else {
-                                STORM_PRINT("  - Do not know if monotone decreasing in: " << itr2->first << std::endl);
+                                    STORM_PRINT(
+                                            "  - Do not know if monotone decreasing in: " << itr2->first << std::endl);
                                 }
                             }
                         }
@@ -126,6 +134,7 @@ namespace storm {
                     }
                     ++i;
                 }
+            }
 
             finalCheckWatch.stop();
             STORM_PRINT(std::endl << "Time for monotonicity check on lattice: " << finalCheckWatch << "." << std::endl << std::endl);