RE: Error in LSODA: Code -5
Nicolas,
The suggested error model comes from the reference below. It relaxes the strong
assumption that the residual error magnitude is the same for all subjects. Such
an assumption would be valid if assay error would be the dominating error, but
it seldom is with clinical data.
Assumption testing in population pharmacokinetic models: illustrated with an
analysis of moxonidine data from congestive heart failure patients.
Karlsson MO, Jonsson EN, Wiltse CG, Wade JR.
J Pharmacokinet Biopharm. 1998 Apr;26(2):207-46.
Best regards,
Mats
Mats Karlsson, PhD
Professor of Pharmacometrics
Dept of Pharmaceutical Biosciences
Faculty of Pharmacy
Uppsala University
Box 591
75124 Uppsala
Phone: +46 18 4714105
Fax + 46 18 4714003
www.farmbio.uu.se/research/researchgroups/pharmacometrics/
Quoted reply history
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of SIMON Nicolas
Sent: Friday, December 11, 2015 8:24 AM
To: Andre Jackson; 'Leonid Gibiansky'; [email protected]
Subject: RE: [NMusers] Error in LSODA: Code -5
Leonid,
You suggest the following residual model:
Y=IPRED*(1+W*EXP(ETA())*EPS())
Could you give more information on it?
Best regards
Nicolas
-----Message d'origine-----
De : [email protected] [mailto:[email protected]] De la
part de Andre Jackson Envoyé : jeudi 10 décembre 2015 21:22 À : 'Leonid
Gibiansky'; [email protected] Objet : RE: [NMusers] Error in LSODA: Code -5
Leonid:
I tried the first suggestion by getting rid of some of the data that was
deficient (i.e., subjects with less than 8 concentrations over the 30 hr.
sampling period) and the LSODA error was not present.
I will also try your other suggestions sequentially to see if they also improve
the analysis.
Thanks for your input.
Andre
-----Original Message-----
From: Leonid Gibiansky [mailto:[email protected]]
Sent: Thursday, December 10, 2015 9:59 AM
To: Andre Jackson; [email protected]
Subject: Re: [NMusers] Error in LSODA: Code -5
Usually this error message is not informative: it just tells you that something
is wrong with the model. It can be fixed by (in the order of
importance)
- cleaning the data (look on concentration-time plots to remove obvious
outliers),
- starting with the better initial parameter values (e.g., your mean analysis
final estimates),
- setting bounds on THETAs,
- removing some ETAs,
- using combined residual error instead of the purely proportional one,
- using residual error with ETAs (instead of Y=IPRED*(1+W*EPS()) use
Y=IPRED(1+W*EXP(ETA())*EPS()),
- other model modifications/simplifications/improvements, including changing
the estimation method (try FO if nothing helps, and then used FO final
estimates to start something more advanced)
Leonid
--------------------------------------
Leonid Gibiansky, Ph.D.
President, QuantPharm LLC
web: www.quantpharm.com
e-mail: LGibiansky at quantpharm.com
tel: (301) 767 5566
On 12/10/2015 8:10 AM, Andre Jackson wrote:
> I have run a control stream that runs okay following MU modeling with
> the mean data to establish the best structural model using NM7 with
> ADVAN 13 TRANS1 TOL=6.
>
> However when I attempt to run the model in a population mode with even
> one eta on a MU I get the following error.
>
> OCCURS DURING SEARCH FOR ETA AT INITIAL VALUE, ETA=0
>
> ERROR IN LSODA: CODE -5
>
> ERROR OCURRED WHILE ATTEMPTING TO OBTAIN INITIAL VALUES FOR ATOL
>
> 0PROGRAM TERMINATED BY OBJ
>
> I have seen some posts in the archives on LSODA and differential
> equations but nothing that seems to address my problem directly.
>
> Does anyone know of any more definitive posts or have suggestions as
> to how best to proceed.
>
> Thanks
>
> Andre Jackson
>
> [email protected] <mailto:[email protected]>
>