Re: ADVAN4!!!
From: LSheiner <lewis@c255.ucsf.edu>
Subject: Re: ADVAN4!!!
Date: Fri, 10 Mar 2000 14:02:51 -0800
SRV,
I haven't tried running your problem so perhaps you really are getting that message, but are you sure? That is, are you sure that in the control stream that gave you the problem you didn't have either of the following:
1. $ESTIMATION ... POSTHOC
2. $ESTIMATION ... METHOD=1 (OR FOCE)
But the main reason I am writing is to alert you and nmusers that there is just no way NONMEM can estimate 10 population variance parameters (a full 5 x 5 cov matrix) with data from only 16 persons, and only ca 3 points/person at that!
You really should use nothing more complicated than
> KA=THETA(1)
> K23=THETA(2)
> K32=THETA(3)
> K=THETA(4)*ETA(1)
> V=THETA(5)*ETA(2)
for starters, with a 2x2 OMEGA.
However, this won't solve the problem you asked about, unfortunately.
LBS.
--
_/ _/ _/_/ _/_/_/ _/_/_/ Lewis B Sheiner, MD (lewis@c255.ucsf.edu)
_/ _/ _/ _/_ _/_/ Professor: Lab. Med., Bioph. Sci., Med.
_/ _/ _/ _/ _/ Box 0626, UCSF, SF, CA, 94143-0626
_/_/ _/_/ _/_/_/ _/ 415-476-1965 (v), 415-476-2796 (fax)