Re: inexplicit equations in PRED
Robert,
You can do it using ADVAN9 with NEQUILIBRIUM option in $MODEL, and $AESINITIAL and $AES blocks. E.g. (where A(13) is what is F in your example) :
$SUBROUTINES ADVAN9 TOL=4
$MODEL NEQUILIBRIUM=1
COMP(COMP1)
....
COMP(COMP13)
$PK
...
$AESINITIAL
INIT = 0; 0=APPROXIMATE, 1=EXACT
A(13)=0.001
$AES
E(13)=A(9)-A(13)-A(13)*A(10)/(KSS+A(13))-A(13)*A(12)/(KSS2+A(13))
$DES
...
$ERROR
Y = A(13)+EPS(1)
Regards,
Katya
--------------------------
Ekaterina Gibiansky, Ph.D.
CEO&CSO, QuantPharm LLC
Web: www.quantpharm.com
Email: [email protected]
Tel: (301)-717-7032
Robert Kalicki wrote:
> Dear NMusers,
>
> Most of the models are pre-defined (ADVANx), expressed as a system of differential equations or provided in the form of an explicit mathematical equation (PRED).
>
> Is it possible to deal with nonlinear inexplicit equations like y = f(x,y) where both differential equations and explicit solution equation are not known or not obvious.
>
> Concretely, using PRED, one would find F on the both sides:
>
> F = f(X) + g(F)
>
> Y = F+EPS(1)
>
> Many thanks in advance
>
> Best regards,
>
> Robert
>
> ___________________________________________
> Robert M. Kalicki, MD
>
> Postdoctoral Fellow
>
> Department of Nephrology and Hypertension
>
> Inselspital
>
> University of Bern
>
> Switzerland
>
> Address:
>
> Klinik und Poliklinik für Nephrologie und Hypertonie
>
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>
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>
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>
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>
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