Package jline.solvers.mam.handlers

Class Solver_mam_ldqbd

java.lang.Object
jline.solvers.mam.handlers.Solver_mam_ldqbd
public final class Solver_mam_ldqbd extends Object
Solver for single-class two-station queueing networks using a Level-Dependent QBD.

Two regimes share one block-tridiagonal generator, differing only in the per-level arrival rate and the top level:

  • CLOSED: one Delay (INF) + one Queue (FCFS), finite population N. Level n is the number of jobs at the queue, and the arrival rate out of level n is the finite-source rate (N-n)*lambda_eff, which vanishes at n = N and closes the chain by itself.
  • OPEN: one Source (EXT) + one Queue, Poisson arrivals at a constant lambda_eff, truncated at options.cutoff or at a level where the tail probability is negligible.

Exactness: exact for exponential service at any number of servers, and for PH service at any number of servers. The multiserver PH chain carries the MULTISET of the phases the min(n,c) busy servers sit in; the collapsed single-phase approximation this solver used until 2026-08-18 is gone.

The blocks come from Solver_mam_ldqbd_statevec.solver_mam_ldqbd_ld(jline.lang.NetworkStruct, jline.solvers.SolverOptions), the one construction shared with the SolverENV state-vector analyzer. This class kept a second, closed-only copy until 2026-08-18, which silently ignored sn.lldscaling (though the featset declared LoadDependence for this method) and refused the open regime that MATLAB, Python and C++ all served.