SIMSCRIPT II.5 Programming Language

Discrete Simulation Concepts
RANDVAR 0.1 0.2 0.35
10 25 40
0.55 0.8 1.0
100 150 200
Use of the random variable:
Figure 5-8. Storage of RANDVAR Sample Values
0
let NEXT.VALUE = RANDVAR
if RANDVAR greater than LIMIT,
.
.
If the input data had the form:
0.1 10 0.1 25 0.15 40 0.2 100 0.25 150 0.2 200 *
the data would be stored in the same form. Individual probability values are accumulated as the
data are read.
Random variables cannot appear in any other form of read statement, because input of a random
variable "value" obviously means something special. If RANDVAR is an attribute of a permanent
entity, one can say read RANDVAR(I) but not read RANDVAR, because the latter statement is interpreted
as a free-form array read statement. Only a single random variable data list can be read
at one time. If RANDVAR is an attribute of a temporary entity, read RANDVAR is interpreted as read
RANDVAR(entity), using implied subscripting.
5.5 Simulation Analysis
The principal outputs of simulation experiments are statistical measurements. Such quantities as the
average length of a waiting line and the percentage of idle time of a machine are typical examples.
Two features, accumulate and tally, provided in SIMSCRIPT II.5, allow such information to
be gathered during a simulation run, without requiring any other explicit action to be specified within
the program. These two preamble statements can instruct the compiler that automatic data collection
and analysis are to be performed at appropriate places in a program. The program text can
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