From: Jaya.Pisupati@quintiles.com
Subject: [NMusers]info on a do-while-loop
Date: Tue, June 1, 2004 6:02 pm
Can anyone provide me with info on what is a "do-while loop' and how can it
be added/coded in a control stream. An example would be great!
Thanks
Jaya Pisupati, PhD
Quintiles, Inc
info on a do-while-loop
From: Nick Holford n.holford@auckland.ac.nz
Subject: RE:[NMusers]info on a do-while-loop
Date: Tue, June 1, 2004 7:06 pm
Jaya,
Do-while loops can only be used with $SIMULATION and when ICALL.EQ.4. The only use I
have found for them is to resample from the ETA and EPS distributions to truncate
the distributions e.g. to ensure that all conc samples are non-negative.
An example is shown below. The ETA sample distribution is truncated so that all
values lie within 99.9% of all possible values. The EPS sample distributions is
truncated so that all values are >= 0.
$PROB THEOPHYLLINE PHARMACODYNAMICS
$DATA theopd.dat IGNORE #
$INPUT ID TIME THEO AGE WT GEND RACE DIAG DV
$SIM (20000625 NORMAL NEW) SUBPROBLEMS=2
$ESTIM PRINT=0 MAXEVAL=9999
$THETA (0,150.,) ; E0
$THETA (0,200.,) ; EMAX
$THETA (.001,10,) ; EC50
$OMEGA 0.5 ; CVE0
$OMEGA 0.5 ; CVEMAX
$OMEGA 0.5 ; CVEC50
$SIGMA 100 ; SD 1
$PRED
E0=THETA(1)*EXP(ETA(1))
EMAX=THETA(2)*EXP(ETA(2))
EC50=THETA(3)*EXP(ETA(3))
IF (ICALL.EQ.4) THEN ; simulation
TRUNC=3.27 ; Z 2tailed alpha=0.01 i.e. include 99.9%
TVE0=E0
E0=TVE0*EXP(ETA(1))
LNMU=LOG(TVE0)
DLTA=TRUNC*0.717 ; MUST BE 3.27*SQRT(CVE0)!
L0=EXP(LNMU-DLTA)
H0=EXP(LNMU+DLTA)
TVEMAX=EMAX
EM=TVEMAX*EXP(ETA(2))
LNMU=LOG(TVEMAX)
DLTA=TRUNC*0.717 ; MUST BE 3.27*SQRT(CVEMAX)!
LM=EXP(LNMU-DLTA)
HM=EXP(LNMU+DLTA)
TVEC50=EC50
C5=TVEC50*EXP(ETA(3))
LNMU=LOG(TVEC50)
DLTA=TRUNC*0.717 ; MUST BE 3.27*SQRT(CVEC50)!
L5=EXP(LNMU-DLTA)
H5=EXP(LNMU+DLTA)
DOWHILE(E0.LT.L0.OR.E0.GT.H0.OR.EM.LT.LM.OR.EM.GT.HM.OR.C5.LT.L5.OR.C5.GT.H5)
CALL SIMETA(ETA)
EMAX=TVEMAX*EXP(ETA(2))
E0=TVE0*EXP(ETA(1))
EC50=TVEC50*EXP(ETA(3))
ENDDO
ENDIF
EFFECT=E0 + EM*THEO/(THEO+C5)
Y = EFFECT + ERR(1)
IF (ICALL.EQ.4) THEN ; simulation
DOWHILE (Y.LT.0)
CALL SIMEPS(EPS)
Y=EFFECT + ERR(1)
ENDDO
ENDIF
$TABLE ID TIME THEO AGE WT GEND RACE DIAG
E0 EM C5 Y
NOPRINT ONEHEADER FILE=theopdsimtrunc.fit
--
Nick Holford, Dept Pharmacology & Clinical Pharmacology
University of Auckland, 85 Park Rd, Private Bag 92019, Auckland, New Zealand
email:n.holford@auckland.ac.nz tel:+64(9)373-7599x86730 fax:373-7556
http://www.health.auckland.ac.nz/pharmacology/staff/nholford/
From: Adrian Dunne Adrian.Dunne@ucd.ie
Subject: RE:[NMusers]info on a do-while-loop
Date: Wed, June 2, 2004 5:23 am
Jaya,
I use DOWHILE loops to simulate binomial data - for example if I want
to simulate N Bernoulli trials each with probability of 'success' given by
P and count the number of 'successes' the code would contain (DV is
the simulated value);
DOWHILE(I.LE.N)
CALL RANDOM(2,R) ; stream 2 contains uniform pseudo random
numbers
IF(R.LE.P) DV=DV+1
I=I+1
ENDDO
Adrian.-------------------------------------------
Adrian Dunne
Department of Statistics
University College Dublin
Belfield
Dublin 4
Ireland
e-mail Adrian.Dunne@ucd.ie
Phone +353-1-7167151
FAX +353-1-7161186
http://www.ucd.ie/~statdept/
From: Jaya.Pisupati@quintiles.com
Subject: RE:[NMusers]info on a do-while-loop
Date: Wed, June 2, 2004 9:37 am
Dr. Holford and Dr. Dunne.
Thanks. The examples were very informative.
Jaya Pisupati
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