Made the -o argument (output folder) optional, so that you can run...

Made the -o argument (output folder) optional, so that you can run high-performance simulations without storing the results.

main.cpp

@@ -39,11 +39,12 @@ void printBasicInfo()
 void printUsageInfo(const std::string& programName)
 {
 	std::cout
-		<< "Usage: " << programName << " -i -o [-t]" << std::endl
+		<< "Usage: " << programName << " -i [-o] [-t]" << std::endl
 		<< "  -i (or -input)     = An XML file describing the simulation scenario to run." << std::endl
 		<< "                       For help on creating scenario files, please see the UMANS documentation." << std::endl
-		<< "  -o (or -output)    = Name of a folder to which the simulation output will be written." << std::endl
+		<< "  -o (or -output)    = (optional) Name of a folder to which the simulation output will be written." << std::endl
 		<< "                       The program will write a CSV file for each agent's trajectory." << std::endl
+		<< "                       If you omit this, the program will run faster, but no results will be saved." << std::endl
 		<< "  -t (or -nrThreads) = (optional, default=1) The number of parallel threads to use." << std::endl << std::endl;
 }
 
@@ -75,26 +76,35 @@ int main( int argc, char * argv[] )
 			nrThreads = atoi(paramValue.c_str());
 	}
 
-	// if any argument is incorrect, show an error
-	if (configFile == "" || outputFolder == "")
+	// input file is mandatory
+	if (configFile == "")
 	{
-		std::cerr << "Input error: Please specify all required arguments." << std::endl;
+		std::cerr << "Input error: Please specify an input scenario." << std::endl;
 		printUsageInfo(argv[0]);
 		return 0;
 	}
 
+	// number of threads must be at least 1
 	if (nrThreads < 1)
 	{
 		std::cerr << "Input error: Please specify a positive number of threads." << std::endl;
 		printUsageInfo(argv[0]);
 		return 0;
 	}
+
+	// output folder may be empty; if so, show a warning
+	if (outputFolder == "")
+	{
+		std::cout << "Input warning: No output folder specified." << std::endl
+			<< "The program will not write any simulation results to CSV files." << std::endl;
+	}
 	
 	// run the simulation
 	CrowdSimulator* cs = CrowdSimulator::FromConfigFile(configFile, true);
 	if (cs != nullptr)
 	{
-		cs->SetCSVOutputDirectory(outputFolder);
+		if (outputFolder != "")
+			cs->SetCSVOutputDirectory(outputFolder);
 		cs->RunSimulationUntilEnd();
 	}