Export pnpro with single-server semantics

src/storm-gspn/storage/gspn/GSPN.cpp

@@ -432,7 +432,10 @@ namespace storm {
             for (auto& trans : timedTransitions) {
                 stream << space3 << "<transition name=\"" << trans.getName() << "\" ";
                 stream << "type=\"EXP\" ";
-                stream << "nservers-x=\"" << trans.getRate() << "\" ";
+                //stream << "nservers-x=\"" << trans.getRate() << "\" ";
+                // Use single-server semantics for GSPNs:
+                // timed rates are independent of number of tokens in input places
+                stream << "nservers=\"1\" ";
                 //Note: The rate is translated to a number showing the decimal figures so GreatSPN can process it
                 stream << "delay=\"" << std::showpoint << trans.getRate() << "\" ";
                 if (transitionLayout.count(trans.getID()) > 0) {