Re: 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
Quoted reply history
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]>