give hint where the optimizers expression parser failes

optimizer/Expression/Expression.h

@@ -178,8 +178,9 @@ private:
 
         if (!success || iter != end) {
             std::cout << "Parsing failed!" << std::endl;
+            std::string here = (iter != end ? std::string(iter, end): expr_);
             throw new OptPilotException("Expression::parse()",
-                                        "Parsing failed!");
+                                         "Parsing failed here: " + here + "!");
         }
 
         // store the functions and variables required to evaluate this

src/Optimize/OpalSimulation.cpp

@@ -429,6 +429,9 @@ void OpalSimulation::collectResults() {
         } catch(SDDSParserException &e) {
             std::cout << "Evaluation of objectives or constraints threw an exception ('" << e.what() << "' in " << e.where() << ")!" << std::endl;
             invalidBunch();
+        } catch(OptPilotException &e) {
+            std::cout << "Evaluation of objectives or constraints threw an exception ('" << e.what() << "' in " << e.where() << ")!" << std::endl;
+            invalidBunch();
         } catch(...) {
             std::cout << "Evaluation of objectives or constraints threw an exception!" << std::endl;
             invalidBunch();
@@ -509,4 +512,4 @@ void OpalSimulation::cleanUp() {
     } catch(...) {
         std::cout << "Can't remove directory '" << simulationDirName_ << "'" << std::endl;
     }
-}
+}
\ No newline at end of file