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The simulation class

The primitives and methods for running and ending the simulation are provided by the simulation class. The simulation class has the following interface :

   interface simulation 
      virtual ~simulation();   
      void run();                      // run until no events left
      void run(double t);              // run for t time units
      void run(int count);             // run for count terminated events
      void quit();                     // quit simulation
      void terminate(event* e);        // terminate e
      int schedule(event* e,double t); // schedule e at t
      int wait(double t);              // schedule current
      int passivate(event* e);         // passivate e
      int activate(event* e);          // activate e
      int hold(event* e);              // add e to conditional
      int withdraw(event* e);          // put e on closed
      int reinstate(event* e);         // put e on conditional

      void reset();                    // reset the simulation

      double clock();                  // return clock

      void init(char* options = "");   // initialize

      int cancel();                    // cancel events

      screen* format(char* p,char* options = "");  // statistics
      screen* format(widget* w,char* p,char* options = "");
      void postscript(char* fn);       // generate postscript
      friend ostream& operator<<(ostream& os,simulation& s);

The simulation object should be created before other objects participating in the program are created. The method run is used to run the simulation for t time units, for count terminated events or until no scheduled events are left. The simulation can be stopped by calling quit. The primitives are described in section 3.2. Reset clears the scheduler and conditional list, resets the clock to 0 and resets the reports and widgets (if set) to their original state. The function clock returns the current simulation time. The init method handles the following options :

If the constructor takes the -realtime argument the library runs in real time mode. A run then ends if the simulation time divided by the double is greater then the actual time (in seconds) that elapsed. If the -scan option is set to yes, the list with the conditional events is traversed, even between events with the same activation time. Setting -suppress has as effect that generated reports and/or statistics are not printed after a run. The method cancel removes and deletes every event from the scheduler and conditional list that receives FALSE from its event::verify method. This method can be used to model the breakdown of a server for example, departure events should be canceled then. The format method creates a screen with the specified path for the statistics and handles the following options : The size can be adjusted but the pre condition is that width/400 is equal to height/120. If format is not used the statistics are printed on a default toplevel screen (if in hush mode). The function postscript writes the window of the simulation object (if created) in postscript format to the specified file. The operator<< function can be used when debugging a program. It prints the contents of the scheduler and conditional list.

next up previous contents
Next: The generator class Up: Program structure Previous: The entity class

A Eliens
Tue Oct 31 09:27:21 MET 1995