SIMSCRIPT II.5 Programming Language

Discrete Simulation Concepts
before the start simulation statement is executed. The origin is set by a call to a library routine.
The arguments to this routine are as shown below:
call origin.r(integer month expression, integer day expression,
integer year expression)
Because simulation time is maintained in time.v and saved in the time.a attribute of event and
process notices as a real number, conversions must be made between calendar specifications and
the SIMSCRIPT II.5 internal representation. The algorithm that performs this conversion assumes
the origin date is a Monday, and that simulation starts at the beginning of that day (00.00 hours).
Time.v is always set to zero at the start of simulation.
Four functions are provided to convert year, month, and day expressions into cumulative simulation
times and vice versa. These functions are described in table 5-4. The examples assume that the
origin time has been set to July 1, 1982, by the call:
call origin.r(7, 1, 82)
Table 5.4 Calendar Date Conversion Functions
Name
Arguments
Function
Mode
Function
Values
Example
date.f
3 INTEGER
expressions
INTEGER
current simulation
day
month, day, year
date.f(7,15,82) =
14
year.f
month.f
REAL time
expression
REAL time
expression
INTEGER current year year.f(476.2) =
1983
INTEGER 1-12 current month month.f(476.2) = 10
day.f
REAL time
expression
INTEGER 1-31
day of current
month
day.f(476.2) = 21
These functions may be used directly within statements to convert from calendar format times. For
example:
schedule a DEPART at date.f(MONTH, DAY, YEAR) + SERVICE.TIME
Sample external event data records, containing no optional data, are:
SERVICE 1/15/80 05 35 *
ARRIVAL 14 05 35 *
DEPART 476.2 *
211