NONMEM Users Network Archive

Hosted by Cognigen

Re: Implementation of the OMEGA covariance matrix

From: Rong Chen <rongchenchn>
Date: Fri, 14 Aug 2015 06:43:02 +0000 (UTC)

Dear Ana,
I think the matrix presented in your email is already able to realize your =
idea if you change '$OMEGA' to '$OMEGA BLOCK(6)'.A value of 0 in OMEGA matr=
ix is considered as it's fixed to this value.
Personall speaking, I suggest you take Elke/Rudy's advice, putting these th=
ree in an $OMEGA BLOCK(3) and list the remaining OMEGAs separately in$OMEGA=
But technically, they are all the same, because the default assumption in $=
OMEGA is that they are diagonal matrices with all off-diagonal elements ass=
umed to be 0.
Best regards,Rong
      From: Ana Miranda Bastos <ana.bastos
 To: "nmusers
 Sent: Tuesday, 28 July 2015, 20:52
 Subject: [NMusers] Implementation of the OMEGA covariance matrix
Dear NMusers,

I wonder if someone could help me to implement the OMEGA covariance matrix =

 0.09  ;  PPV_VMAX
 0.00 0.09  ;    PPV_V1
 0.00 0.00 0.09  ;    PPV_V2
 0.00 0.00 0.00 0.09  ;    PPV_KD
 0.00 0.01 0.00 0.00 0.09  ;  PPV_BMAX
 0.00 0.01 0.00 0.00 0.01 0.09  ;    PPV KM

I don't want to fix any value to zero, but I don't know how to better illus=
trate that I would like to consider a covariance between:
. V1 and Bmax
. Bmax and Km
. V1 and Km

Any advice is highly appreciated. Thank you in advance.

Kind regards,


Ana Bastos, Pharm, MSc, PhD student
Pharmacologie cellulaire et moléculaire
(Cellular and Molecular Pharmacology Unit)
Louvain Drug Research Institute
Université catholique de Louvain (Catholic University of Louvain)
UCL 7370 avenue E. Mounier 73
1200 Bruxelles, Belgique

Received on Fri Aug 14 2015 - 02:43:02 EDT

The NONMEM Users Network is maintained by ICON plc. Requests to subscribe to the network should be sent to:

Once subscribed, you may contribute to the discussion by emailing: