InventoryCRN.java

package tutorial;
 
import umontreal.ssj.stat.Tally;
import umontreal.ssj.util.Chrono;
 
// Class to simulate and compare two different (S,s) policies with CRNs.
public class InventoryCRN extends Inventory {
 
   Tally statDiff = new Tally("stats on difference");
 
   public InventoryCRN(double lambda, double c, double h, double K, double k, double p) {
      super(lambda, c, h, K, k, p);
   }
 
   public void simulateDiffIRN(int n, int m, int s1, int S1, int s2, int S2) {
      statDiff.init();
      for (int i = 0; i < n; i++) {
         double value1 = simulate(m, s1, S1);
         double value2 = simulate(m, s2, S2);
         statDiff.add(value2 - value1);
      }
   }
 
   public void simulateDiffCRN(int n, int m, int s1, int S1, int s2, int S2) {
      statDiff.init();
      streamDemand.resetStartStream();
      streamOrder.resetStartStream();
      for (int i = 0; i < n; i++) {
         double value1 = simulate(m, s1, S1);
         streamDemand.resetStartSubstream();
         streamOrder.resetStartSubstream();
         double value2 = simulate(m, s2, S2);
         statDiff.add(value2 - value1);
         streamDemand.resetNextSubstream();
         streamOrder.resetNextSubstream();
      }
   }
 
   public static void main(String[] args) {
      InventoryCRN system = new InventoryCRN(100.0, 2.0, 0.1, 10.0, 1.0, 0.95);
      Chrono timer = new Chrono();
 
      system.simulateDiffIRN(500, 2000, 80, 198, 80, 200);
      system.statDiff.setConfidenceIntervalStudent();
      System.out.println(system.statDiff.report(0.9, 3));
      double varianceIndep = system.statDiff.variance();
      System.out.println("Total CPU time: " + timer.format() + "\n");
 
      timer.init();
      system.simulateDiffCRN(500, 2000, 80, 198, 80, 200);
      System.out.println(system.statDiff.report(0.9, 3));
      double varianceCRN = system.statDiff.variance();
      System.out.println("Total CPU time: " + timer.format());
      System.out.printf("\nVariance ratio:  %8.4g%n", varianceIndep / varianceCRN);
   }
}