RE: Interindividual variability in residual variance

-----Original Message----- From: [EMAIL PROTECTED] on behalf of Samtani, Mahesh [PRDUS] Sent: Wed 7/11/2007 2:26 PM To: [email protected] Subject: [NMusers] Interindividual variability in residual variance Dear NMusers, I have run in to an old problem that Vladimir once described here on the users net. I am trying to implement inter-individual variability in residual variance and the corresponding OMEGA is not being iterated. Usually, in Dr. Karlsson's work this error structure is implemented on a proportional or proportional+additive EPS model. I am wondering if my problem is because I am trying to implement ETA on EPS using the transform both sides approach as follows? $ERROR CALLFL=0 IPRED = -5 IF (F.GT.0) IPRED = LOG(F) IRES=DV-IPRED W=1 IWRES=IRES/W Y = IPRED + EXP(ETA(.))*EPS(1) Kindly advice...MNS --------Cut here From: "Piotrovskij, Vladimir [PRDBE]" - [EMAIL PROTECTED] Subject: [NMusers] Implementation of interindividual variability in residual variance Date: 2/17/2004 9:37 AM Dear NONMEM users, I am trying to implement an interidividual variability in the residual variance using an additional random effect: $ERR Y = F + EXP(ETA(.))*EPS(1) It turned out the corresponding OMEGA was not iterated, and the final estimate did not differ from the initial value. Below is an example control stream and the output illustrating the problem (Note, the actual model I work with is more complicated). Thanks in advance. Best regards, Vladimir --------Cut here