fixed case where no location variables were provided

src/storm-conv/settings/modules/JaniExportSettings.cpp

@@ -39,15 +39,17 @@ namespace storm {
             }
 
             std::vector<std::pair<std::string, std::string>> JaniExportSettings::getLocationVariables() const {
-                std::string argument = this->getOption(locationVariablesOptionName).getArgumentByName("variables").getValueAsString();
-                std::vector<std::string> arguments;
-                boost::split( arguments, argument, boost::is_any_of(","));
                 std::vector<std::pair<std::string, std::string>> result;
-                for (auto const& pair : arguments) {
-                    std::vector<std::string> keyvaluepair;
-                    boost::split( keyvaluepair, pair, boost::is_any_of("."));
-                    STORM_LOG_THROW(keyvaluepair.size() == 2, storm::exceptions::IllegalArgumentException, "Expected a name of the form AUTOMATON.VARIABLE (with no further dots) but got " << pair);
-                    result.emplace_back(keyvaluepair.at(0), keyvaluepair.at(1));
+                if (isLocationVariablesSet()) {
+                    std::string argument = this->getOption(locationVariablesOptionName).getArgumentByName("variables").getValueAsString();
+                    std::vector<std::string> arguments;
+                    boost::split( arguments, argument, boost::is_any_of(","));
+                    for (auto const& pair : arguments) {
+                        std::vector<std::string> keyvaluepair;
+                        boost::split( keyvaluepair, pair, boost::is_any_of("."));
+                        STORM_LOG_THROW(keyvaluepair.size() == 2, storm::exceptions::IllegalArgumentException, "Expected a name of the form AUTOMATON.VARIABLE (with no further dots) but got " << pair);
+                        result.emplace_back(keyvaluepair.at(0), keyvaluepair.at(1));
+                    }
                 }
                 return result;
             }