RE: [NMusers] RE: re: bug in NONMEM VI?

Hi all,
 
Bill is right. SLOW in NONMEM version 6 works fine giving the better =
answer in the minimization problem (FO method). Peter is also right in =
that COV3 and COV4 are more correlated than with the others! I suppose =
NONMEM version 5 was inherently SLOW (!)?
 
Thanks and have a great new year!
 
John
 

John C Lukas

Strategic Consulting Services

Pharsight Corp.

 

line: + 33 492 726 495

cell: + 33 626 496 777


________________________________

From: Bonate, Peter [mailto:Peter.Bonate_at_genzyme.com]
Sent: Wed 1/2/2008 10:03 PM
To: Bill Bachman; John Lukas; nmusers_at_globomaxnm.com
Subject: RE: [NMusers] RE: re: bug in NONMEM VI?


I'd also like to see how correlated COV3 and COV4 are. This may be a =
collinearity issue.
 
pete bonate
 
Peter L. Bonate, PhD, FCP
Genzyme Corporation
Senior Director
Clinical Pharmacology and Pharmacokinetics
4545 Horizon Hill Blvd
San Antonio, TX 78229 USA
peter.bonate_at_genzyme.com
phone: 210-949-8662
fax: 210-949-8219
crackberry: 210-315-2713
 

________________________________

From: owner-nmusers_at_globomaxnm.com [mailto:owner-nmusers_at_globomaxnm.com] =
On Behalf Of Bill Bachman
Sent: Wednesday, January 02, 2008 2:38 PM
To: 'John Lukas'; nmusers_at_globomaxnm.com
Subject: RE: [NMusers] RE: re: bug in NONMEM VI?



Have you tried both of these runs using the SLOW option on the =
estimation record?

 

________________________________

From: owner-nmusers_at_globomaxnm.com [mailto:owner-nmusers_at_globomaxnm.com] =
On Behalf Of John Lukas
Sent: Wednesday, January 02, 2008 2:36 PM
To: nmusers_at_globomaxnm.com
Subject: [NMusers] RE: re: bug in NONMEM VI?

 

 

 

________________________________

From: John Lukas
Sent: Mon 12/17/2007 11:51 PM
To: nmusers_at_globomaxnm.com
Subject: re: bug in NONMEM VI?

Dear Nmusers,

 

A simple LME model run using NM version VI, FO method, with 4 covariates =
(5 THETA's) as,

.

.

$PRED

 

SUM1=THETA(2)*COV1+THETA(3)*COV2

SUM2=THETA(4)*COV4+THETA(5)*COV3

 

TLAU=THETA(1)+SUM1+SUM2

F=TLAU+ETA(1)

 

Y=F+EPS(1)

 

$THETA 4 .1 .1 .1 .1

$OMEGA .1

$SIGMA .1

 

$ESTIMATION MAXEVALS=1900 PRINT=5 METHOD=0

 

(let's call this FIT A) gave a different fit from another (FIT B) where =
only the order of THETA( 4) and 5 was reversed, all else kept the same, =
as,

.

.

SUM2=THETA(5)*COV4+THETA(4)*COV3

.

.

(even more strange, FIT B, the reversed order run, proved to be the good =
run!)

 

NONMEM version V had the same result for both FITS A and B, as expected =
(and same as FIT B from version 6). FOCE gave good answers always in =
both NONMEM version V and version VI. But, the question remains about =
that dependence on ordering of the THETAs with the FO method for version =
VI.

 

Any comments? Has there been discussion on this earlier that I missed? =
Thanks in advance.

 

John

PS I am aware of other *important* incosistencies between version VI and =
V from university colleagues working on a PK problem with FOCE...

 

 

John C Lukas

Strategic Consulting Services

Pharsight Corp.

 

line: + 33 492 726 495

cell: + 33 626 496 777

 

 


Received on Thu Jan 03 2008 - 02:51:51 EST