Re: 3 compartment nonlinear pharmacokinetics model

From: Nick Holford <n.holford@auckland.ac.nz> Subject: Re: [NMusers] 3 compartment nonlinear pharmacokinetics model Date: Thu, 15 Nov 2001 13:09:44 +1300 Yungwei Hsu wrote: > > Dear Dr. Holford, > > Thank you very much for your generous help. > After running the NONMEM, I got > > V1 V max Km V2 CL2 > V3 CL3 > > 5.83 1.17 0.746 121 0.630 > 37 1.23 > > and the following message > ====================================== > MINIMIZATION SUCCESSFUL > NO. OF FUNCTION EVALUATIONS USED: 1038 > NO. OF SIG. DIGITS IN FINAL EST.: 3.1 > S MATRIX ALGORITHMICALLY SINGULAR > T MATRIX SET EQUAL TO RS*R, WHERE S* IS A PSEUDO INVERSE OF S > =================================================================== > What does this means? My control file is as follows, It means you were very lucky!! Most of the time NONMEM has trouble computing the COVARIANCE step but by some trickery it can get a reasonably close approximation. That is what the messages about the various matrices are about. -- Nick Holford, Divn Pharmacology & Clinical Pharmacology University of Auckland, 85 Park Rd, Private Bag 92019, Auckland, New Zealand email:n.holford@auckland.ac.nz tel:+64(9)373-7599x6730 fax:373-7556 http://www.health.auckland.ac.nz/pharmacology/staff/nholford/