Power Function Model
I would like to know if some users had problems with using the power
function model.
I have tried to fit my data with the power function model. My data are
quite simple : twenty-three 15min IV infusion full profile. The NM-TRAN
control file is the following :
$PROB TWO COMPARTMENTS / ALL SUBJECTS : IV
$INPUT PRN ID TIME DV AMT RATE EVID
$DATA
$SUBROUTINE ADVAN3 TRANS3
$PK
TVCL=THETA(1)
CL=TVCL*EXP(ETA(1))
TVV=THETA(2)
V=TVV*EXP(ETA(2))
TVQ=THETA(3)
Q=TVQ*EXP(ETA(3))
TVVSS=THETA(4)
VSS=TVVSS*EXP(ETA(4))
S1=V
$THETA (0,80) (0,20) (0,90) (50,70) (0,0.5,1)
$OMEGA 0.5 0.5 0.5 0.5
$ERROR
W=F**THETA(5)
Y=F+W*EPS(1)
IPRED=F
IRES=DV-IPRED
IWRES=IRES/W
$SIGMA 0.25
$ESTIMATION MAXEVALS=7000 PRINT=5 METHOD=0 NOABORT POSTHOC
$COVARIANCE
$TABLE PRN ID CL V Q VSS IPRED IWRES NOPRINT FILE=
$TABLE PRN ID TIME ETA1 ETA2 ETA3 ETA4
$SCATTER PRED VS DV UNIT
$SCATTER PRED VS TIME
$SCATTER WRES VS PRED
$SCATTER IWRES VS IPRED
NONMEM is running on VAX station.
I get get the following error message :
Job terminated with error status %MTH-F-UNDEXP, undefined exponentiation!/
user PC !XL.
Could you tell me if there is any problem with the power function model, or
if I am not using it correctly?