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Interface Summary
Interface |
Description |
MMcDelay |
Interface for ErlangA and ErlangC queueing model objects.
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Class Summary
Class |
Description |
ErlangA |
The Erlang A formula assumes similar hypothesis as the Erlang C, however Erlang A
assumes the possibility of abandonment of clients waiting in the queue.
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ErlangB |
The Erlang B formula is used to compute the blocking probability
in M/M/c queueing model assuming no queue capacity.
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ErlangC |
The Erlang C formula is used to compute the delay probability
Pr{W > 0}
and also the service level, defined as
Pr{W <= awt}, where W is the
waiting time and awt the acceptable waiting time.
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Package umontreal.iro.lecuyer.ccoptim.approx.mmc Description
This package implements the approximation formulas of Erlang A, B and C
for the M/M/c queueing model.
The model assumes a Poisson arrival process, exponential service time and
exponential patience time.
In a loss model, there are no waiting queue. In the delay model, a call
can abandon if its waiting time is greater than its patience time.
For the Erlang C formula, we can assume an infinite queue capacity (using the
tractability of the formula) or a limited capacity.
For the Erlang A formula, the user must give a limited capacity to the queue.
The exact Erlang A formula can be numerically unstable for large queue with many
servers. We have also implemented the approximation of the Erlang A formulas
proposed by
Garnett et al. (2002).