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[NMusers] Zeros in OMEGA matrix

From: Gavin Jarvis <>
Date: Fri, 3 Jul 2015 14:58:31 +0100

Dear NMUsers


I have a problem and hope someone might be able to help. In summary, is it
possible for NONMEM to model an OMEGA matrix with four elements (W,X,Y,Z)
such that two of the covariances are fixed to zero and the rest freely
determined? I realise NONMEM can model BAND matrices, but I can't see how to
fix just two covariances to zero. The final matrix structure I'm looking for
would look something like.



C(w,x) Sx

0 C(x,y) Sy

0 C(x,z) C(y,z) Sz


I hope that makes sense. If so, is it possible?


Many thanks





Dr Gavin E Jarvis MA(Cantab) MA PhD VetMB MRCVS

University Lecturer in Veterinary Anatomy

Department of Physiology, Development & Neuroscience

Physiological Laboratory

Downing Street



Tel: +44 (0) 1223 333745


Fellow and College Lecturer in Pharmacology

Tutor for Graduate Students

Selwyn College



Tel: +44 (0) 1223 761303


Email: <>

Web: <>

Twitter: _at_GavinEJarvis


Received on Fri Jul 03 2015 - 09:58:31 EDT

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