RE: [NMusers] Error in LSODA: Code -5

From: <E.Olofsen_at_lumc.nl>
Date: Fri, 11 Dec 2015 14:40:17 +0000

Usually tolerance criteria for ODE solvers apply to the solution at the end=
 of an integration interval. In that case, there is a difference between t=
he solution at some time instant if it is preceded by an observation record=
 with MDV=1 or not. So the tolerance settings for ADVAN13 which are ok f=
or the "normal" subjects could be problematic for the "deficient" subjects =
if an integration interval gets too large. So perhaps adding missing obser=
vation records in between could help preventing LSODA errors. =

Erik =
________________________________________ =
From: owner-nmusers_at_globomaxnm.com [owner-nmusers_at_globomaxnm.com] on behalf=
 of Andre Jackson [jacksonan1945_at_gmail.com] =
Sent: Thursday, December 10, 2015 9:22 PM =
To: 'Leonid Gibiansky'; nmusers_at_globomaxnm.com =
Subject: 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:lgibiansky_at_quantpharm.com] =
Sent: Thursday, December 10, 2015 9:59 AM =
To: Andre Jackson; nmusers_at_globomaxnm.com =
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 changin=
g =
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 =
> =
> Jacksonan1945_at_Gmail.com <mailto:Jacksonan1945_at_Gmail.com> =
> =
Received on Fri Dec 11 2015 - 09:40:17 EST

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