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Re: How to generate a random number with $EST

From: Nieves Vélez de Mendizabal <nvelez>
Date: Tue, 15 Mar 2011 15:43:31 +0100

Dear nmusers,

Thanks everybody. The generation of a random number from a uniform
distribution finally works. Below you can see the code. You also you can
see the table that NONMEM7 generated. The generated random values can be
seen at the 6th column.
  The aim of this model is to estimate a parameter (PERT) that I use to
predict a probability (PROB). Such probability represents the
probability of suffering one event. There is individual variability in
such probability. During the estimation process I have to produce a
train of events for every individual. I don't know yet if it makes sense
to do that in the way I'm trying to, but I thought it could be worth it.

$PK
.....
PERT=THETA(3)*EXP(ETA(1))
PROB=EXP(PERT)/(1+EXP(PERT))
...
$DES
PER=0
KK=0
"KK=RAND(0)
IF (KK.LT.PROB) THEN ;perturbation
     PER=1
ENDIF
....
$ESTIMATION MAXEVAL=9990 NUMERICAL METHOD=COND LAPLACE LIKE CENTERING
PRINT=1 NOABORT MSFO=msfo5
$TABLE ID TIME DV PER PROB KK PER NOAPPEND ONEHEADER NOPRINT FILE=sdtab5

TABLE NO. 1
  ID TIME DV PER PROB KK
   1.0000E+00 1.0000E+00 0.0000E+00 1.0000E+00 5.2498E-01 2.1428E-01
   1.0000E+00 2.0000E+00 1.0000E+00 0.0000E+00 5.2498E-01 6.6192E-01
   1.0000E+00 3.0000E+00 1.0000E+00 0.0000E+00 5.2498E-01 7.7577E-01
   1.0000E+00 4.0000E+00 0.0000E+00 0.0000E+00 5.2498E-01 6.1920E-01
   1.0000E+00 5.0000E+00 0.0000E+00 1.0000E+00 5.2498E-01 1.6852E-01
   1.0000E+00 6.0000E+00 1.0000E+00 1.0000E+00 5.2498E-01 2.1436E-01
   1.0000E+00 7.0000E+00 0.0000E+00 0.0000E+00 5.2498E-01 6.9345E-01
   1.0000E+00 8.0000E+00 0.0000E+00 0.0000E+00 5.2498E-01 5.6443E-01
   1.0000E+00 9.0000E+00 1.0000E+00 0.0000E+00 5.2498E-01 6.0616E-01
   1.0000E+00 1.0000E+01 0.0000E+00 0.0000E+00 5.2498E-01 8.2914E-01
   1.0000E+00 1.1000E+01 0.0000E+00 0.0000E+00 5.2498E-01 5.9900E-01
   1.0000E+00 1.2000E+01 1.0000E+00 0.0000E+00 5.2498E-01 7.6669E-01
   1.0000E+00 1.3000E+01 0.0000E+00 0.0000E+00 5.2498E-01 8.5406E-01
   1.0000E+00 1.4000E+01 0.0000E+00 0.0000E+00 5.2498E-01 8.0210E-01

--
--------------------------------
Nieves Velez de Mendizabal, Ph.D
Departamento de Farmacia y Tecnologa Farmacutica
Facultad de Farmacia
Universidad de Navarra
Phone: (+34) 658 732 851
Phone: (+34) 948 255 400 ext. 5827
nvelez
--------------------------------


Received on Tue Mar 15 2011 - 10:43:31 EDT

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