# Erlang A Formula Calculator

This script evaluates the performance measures
(service level, delay probability, abandonment ratio and
average waiting time)
of a queueing system using the Erlang A formula.
The difference with Erlang C is that Erlang A includes customer abandonments.
Each customer has an exponentially distributed random patience time.
A customer abandons (and exits) the queue when his waiting time exceeds his patience time.
Because of abandonments, this queueing system is always stable.

There are also different ways to define the service level.
Our program offers two service level formulas and an approximation formula
based on diffusion equations (see details in performance measures
section).

This script executes the Erlang A program implemented in the
CCOptim Java
library for call centers.

See the instructions for usage details.