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| RANDOM |
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MEANING: RANDOM subroutine
CONTEXT: NONMEM utility routine
USAGE:
INTEGER KR
REAL R
CALL RANDOM (KR,R)
DISCUSSION:
The NONMEM utility routine RANDOM may be called (by PRED, PK or ERROR)
during the Simulation Step (ICALL=4) and when data averages are being
computed (ICALL=5) to obtain numbers from different random sources.
Input argument:
KR An integer variable or integer constant. The index of a random
source.
Output argument:
R A number from the KRth source. Always a single-precision number.
Each time RANDOM is called, a new number is output.
Random sources are defined using the $SIMULATION record. Typically,
the first source is reserved by NONMEM to generate realizations of the
eta and epsilon variables and/or to randomly mix individuals into dif-
ferent subpopulations according to the mixing parameter. Thus, typi-
cally, RANDOM must be called with KR > 1. However, there are cases
when NONMEM itself needs no random sources, and all defined random
sources can be used by PRED (see references).
EXAMPLES OF USAGE:
WT (an item in the data record, and a local variable with the same
name) is generated with a simulated value having mean 70 and standard
deviation 7. The second random source is assumed to be pseudo-normal,
which is the default distribution for each random source.
An abbreviated code may use RANDOM explicitly in either a simulation
or a data average block. When RANDOM is called in abbreviated code, R
is reserved and is used for the random number. E.g.,
IF (ICALL.EQ.4.AND.NEWIND.NE.2) THEN
CALL RANDOM(2,R)
ENDIF
IF (ICALL.EQ.4) WT=70+7*R
REFERENCES: Guide IV Section III.B.13, IV.I
REFERENCES: Guide V Section 12.4.8
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