Gavin,
NM can not estimate the type of matrix that you have described.
I would suggest adding C(w,y). It may be poorly estimated but you can
always comment that it was added to allow estimation of the others.
Hope it works out for you,
Luann
On 7/3/2015 9:58 AM, Gavin Jarvis wrote:
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...
Sw
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
Gavin
__________________________________________________
*Dr Gavin E Jarvis MA**(Cantab)**MA PhD VetMB MRCVS*
University Lecturer in Veterinary Anatomy
Department of Physiology, Development & Neuroscience
Physiological Laboratory
Downing Street
Cambridge
CB2 3EG
Tel: +44 (0) 1223 333745
Fellow and College Lecturer in Pharmacology
Tutor for Graduate Students
Selwyn College
Cambridge
CB3 9DQ
Tel: +44 (0) 1223 761303
Email: [email protected] <mailto:[email protected]>
Web: www.pdn.cam.ac.uk/staff/jarvis
<http://www.pdn.cam.ac.uk/staff/jarvis>
Twitter: @GavinEJarvis
--
*Luann Phillips*| Director, Pharmacometrics
Cognigen Corporation, a wholly owned subsidiary of Simulations Plus, Inc.
1780 Wehrle Drive, Suite 110 | Buffalo, NY 14221-7000
Phone: 716.633.3463 x236 | Fax: 716.633.7404 |
[email protected] <mailto:[email protected]>
