[NMusers] BAYES Estimation: OBJECTIVE FUNCTION IS INFINITE

From: Xinting Wang <wxinting1986_at_gmail.com>
Date: Fri, 12 Jun 2015 10:06:07 +0800

Dear All,

I am using a cascade of the EM estimation methods implemented in Nonmem 7.2
to solve a high-dimension PK/PD problem. The estimation chain is coded as
below:

$EST MET=SAEM INTER NBURN=2000 NITER=1000 PRINT=5 NOABORT NOPRIOR=
=0
ISAMPLE=10 SIGL=6 CTYPE=3 IACCEPT=0.4 CONSTRAIN=1 SEED=145612 F=
ILE=Saem.ext

$EST MET=IMP INTER NITER=2000 ISAMPLE=1000 PRINT=5 SEED=581987 SI=
GL=6,
CTYPE=3 MAPITER=0 FILE=Imp.ext

$EST MET=BAYES INTER NBURN=3000 NITER=25000 PRINT=10 NOABORT NOPRIO=
R=0
FNLETA=0 ISAMPLE_M1=2 ISAMPLE_M2=2 ISAMPLE_M3=2 IACCEPT=0.4 SEED=
=231457
FILE=Bayes.ext

​The first two estimation methods run successfuly with a convergenc=
e, but
when it comes to BAYES, an error message always occurs:

​ OBJECTIVE FUNCTION IS INFINITE. PROBLEM ENDED
1THERE ARE ERROR MESSAGES IN FILE PRDERR

​I put safety brakes in the code to prevent ​0**power or sq=
uare root of
negative values, but the problem still occured. Setting lower and upper
bound of the initial estimation, but it did not help either.

I am wondering if anyone here encountered this issue previously? It seems
quite strange to me that SAEM and IMP could succeed, but BAYES fails. Could
you please let me know of the possible reasons behind this? Thanks very
much.

Best Regards

--
Xinting

Received on Thu Jun 11 2015 - 22:06:07 EDT

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