Package jline.api.pfqn.mva

Class Pfqn_cntol

java.lang.Object
jline.api.pfqn.mva.Pfqn_cntol
public final class Pfqn_cntol extends Object
Termination cutoff 1/(4000 + 16*sum(N)) of the Linearizer. Published in K. M. Chandy, D. Neuse, "Linearizer: A Heuristic Algorithm for Queuing Network Models of Computing Systems", Commun. ACM 25(2):126-134, 1982, p.129 and appendix. The iteration continues while max_{i,r} |Q^I(i,r) - Q^{I-1}(i,r)| / N_r > 1/(4000 + 16*|N|), |N| = sum(N). The paper motivates the scaling with |N|: at large populations removing one job changes the queue lengths very little, so a fixed cutoff would terminate the iteration prematurely. It also notes that the expression stays below 0.00025 even at very small populations. The same expression is what LQNS uses as its termination test, set in the SchweitzerCommon constructor of libmva/src/mva.cc; that code carries no citation, and the paper above is its source. Passing NaN as the tol argument of pfqn_bs / pfqn_egflinearizer selects BOTH this cutoff and the normalized-maximum metric of the paper, which is the published test; passing pfqn_cntol(N) as a plain number selects only the cutoff, with those methods' own convergence metric. NaN is the sentinel because it cannot collide with any legitimate tolerance and it is the one form the MATLAB, Python and C++ twins share (MATLAB and Python additionally accept the string 'cn').
Since:
LINE 3.0

  • Method Details

    • pfqn_cntol

      public static double pfqn_cntol(Matrix N)
      Termination cutoff at the given population vector.

    • pfqn_cntol

      public static double pfqn_cntol(double totalPopulation)
      Termination cutoff at the given total population.

    • isCntol

      public static boolean isCntol(double tol)
      True when tol is the sentinel requesting the Chandy-Neuse test.