NONMEM Users Network Archive

Hosted by Cognigen

[NMusers] RE: nonmem question regarding condition number

From: Carolina Consuelo Llanos Paez <c.llanospaez_at_uq.edu.au>
Date: Thu, 24 Mar 2016 11:41:49 +0000

Hi Laureen,


When a condition number exceeding 1000 is indicative of severe ill conditio=
ning, which means that you model ?is over-parameterized?.


Please check these links:


http://www.cognigencorp.com/nonmem/nm/99may012003.html

http://www.cognigencorp.com/nonmem/current/2008-February/4212.html?



Carolina

PhD candidate

________________________________

De: owner-nmusers_at_globomaxnm.com <owner-nmusers_at_globomaxnm.com> en nombre d=
e L.A. ten Berg - Lammers <l.a.tenberg-lammers_at_amc.uva.nl>
Enviado: jueves, 24 de marzo de 2016 20:10
Para: 'nmusers_at_globomaxnm.com'
Asunto: [NMusers] nonmem question regarding condition number

Dear nmusers,
I am currently analyzing PK profiles after a single iv adminstration. Volun=
teers were sampled frequently: 12 samples per curve.
For the structural model 2- and a 3-compartment models are compared. The CW=
RES vs time plot of the 2-compartment shows the typical wave, indicative fo=
r a 3-compartment model. Introduction of a third compartment eliminated the=
 wave, OFV decreased with 180 points, precision of the estimates did change=
 notably, but the condition number increased from 998 to 2.0*E16.
Does anyone know how to interpret this large increase in condition number?
Best wishes,
Laureen ten Berg


[Beschrijving: cid:image001.gif_at_01CD804B.C9EE1BA0]




Laureen ten Berg-Lammers

    Hospital Pharmacist


Academisch Medisch Centrum
Universiteit van Amsterdam




Meibergdreef 9 | 1105 AZ Amsterdam | Room: M01-224
Tel: +31(0)20-5662726 | Pager *62726 | l.a.tenberg-lammers_at_uva.amc.nl




________________________________

AMC Disclaimer : https://www.amc.nl/disclaimer

________________________________


image001.gif
(image/gif attachment: image001.gif)

Received on Thu Mar 24 2016 - 07:41:49 EDT

The NONMEM Users Network is maintained by ICON plc. Requests to subscribe to the network should be sent to: nmusers-request_at_iconplc.com. Once subscribed, you may contribute to the discussion by emailing: nmusers@globomaxnm.com.