Class Pfqn_is

java.lang.Object
jline.api.pfqn.nc.Pfqn_is

public final class Pfqn_is extends Object
Importance-sampling (IS) estimate of the normalizing constant of a closed LOAD-INDEPENDENT product-form queueing network with M single-server queues of per-class demand L and an aggregated delay of think time Z.

This is the load-independent case of Pfqn_ld_is (capacities mu_i(k) = 1), and the ordinary-network counterpart of the order-independent

invalid reference
Pfqn_oi_is
and the pass-and-swap Pfqn_pas_is: all four are the same sample-an-ordering estimator, differing only in the per-position factor of each station's balance function. For a single-server queue that factor is the demand of the class at that position, L(i,q_p); for the delay it is Z(q_p)/p; for an OI/P&S station it is the reciprocal rank rate 1/mu_i(supp(q_1..q_p)).

Writing ell = sum(N), an ordering c of all ell jobs is drawn by placing a uniformly random present class at each step (probability p(c) = product of the reciprocal branching factors), and the sum over ALL ways of cutting c into contiguous per-station segments is computed exactly by dynamic programming: G(N) = E_{C~p}[ S(C)/p(C) ], which is unbiased for the exact constant of Pfqn_nc.

Port of matlab/src/api/pfqn/pfqn_is.m.

See Also:
  • Method Details

    • pfqn_is

      public static Ret.pfqnNc pfqn_is(Matrix L, Matrix N, Matrix Z, SolverOptions options)
      Importance-sampling estimate of the load-independent normalizing constant.
      Parameters:
      L - (M x R) per-class service demands at the M single-server queues.
      N - (1 x R) closed population vector, finite.
      Z - (1 x R) aggregated think time (delay) demand; null or zeros if none.
      options - solver options; uses options.samples and options.seed.
      Returns:
      G and lG = log(G).