DO WHILE

DOWHILE may be used in all blocks of abbreviated code:

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 $ABBR DECLARE DOWHILE ILOOP $PK
 ILOOP=1
 DOWHILE (condition)
  .. statements ..
 ILOOP=ILOOP+1
 ENDDO

DOWHILE blocks allow loops in abbreviated code. Previously, they were permitted only in initialization-finalization, simulation, data aver- age, and expectation blocks. See the separate descriptions of these blocks. With NONMEM 7.3, DOWHILE may also be used in data-analytic blocks (i.e., in code that is executed at ICALL=2).

When it is used in data-anlytic code, DOWHILE must be used with a looping variable. Such a variable meets three criteria:

It is declared as such, e.g. $ABBR DECLARE DOWHILE ILOOP
It is given a value in the statement immediately before DOWHILE
It is given a value in the statement immediately before ENDDO.

Usually, the looping variable will be tested in the condition, but this is not necessary.

DOWHILE blocks may be nested.
DOWHILE blocks may not include IF/THEN/ENDIF blocks. Only single-statement IF statements are permitted. E.g., IF (condition) statement
Subscripted variables may be used within the block. These are variables that have been declared arrays using the $ABBR statement, or subscripted reserved variables such as THETA. Subscripts may be integer expressions using declared integer variables and integer values. E.g.
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$ABBR DECLARE X(10) $ABBR DECLARE DOWHILE ILOOP ... $PK ILOOP=1 DOWHILE (condition) X(ILOOP)=THETA(ILOOP+1) ILOOP=ILOOP+1 ENDDO
A DOWHILE loop may compute recursive random variables. These are variables that are modified recursively in a dowhile block and which have eta derivatives. For example,
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TERM=THETA(1)*EXP(ETA(1)) SUM=0 ILOOP=1 DO WHILE(ILOOP<=IMAX) SUM=SUM+TERM ILOOP=ILOOP+1 ENDDO
The DOWHILE recursive variable must be initialized to a non-random variable outside the loop and must appear on both sides of the equal sign only once within the DOWHILE loop: V= … V …

The syntax is limited, for example the following are not permitted:

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  ILOOP=1
  DO WHILE(ILOOP<=IMAX)
  IF (ILOOP == 1) SUM=0  ; initialization within the loop
  SUM=SUM+TERM
  ILOOP=ILOOP+1
  ENDDO

  ILOOP=1
  DO WHILE(ILOOP<=IMAX)
  IF (ILOOP == 1) THEN
  SUM=0                  ; initialization within the loop
  ELSE                   ; else statement
  SUM=SUM+TERM
  ENDIF
  ILOOP=ILOOP+1
  ENDDO

The looping variable ILOOP may also be set and tested and incremented with different integers than shown. EXAMPLES: Several examples are present in the examples directory: Auto-correlation (See ar1mod.ctl) Auto-correlation with Simulation (See ar1newsim.ctl). Dose Superposition (See sumdosetn.ctl) Summing elements of THETA (See superid3_6.ctl)