R help - Feb 2012 - Non linear regression with complex equation

Hi all,
Is it possible to model a function where the unknown parameter appears both
in the fitted equation AND in the determination of other parameters?  E.g.

y = a^2 + b/2 + k

where a = 2/k  and b = k^2 

and the model needs to determine k?  I know this is a very simple equation
(its just an example), the one I am modelling is much more complicated! 

k appears in the equation which the n.l.r model fits, but it also affects
other parameters in the equation.  Please let me know if you know a way of
achieving this.  I realise it is possible to set up a loop where the
modelled value for k is fed back in to a and b, and the model is run again -
but it seems like there should be a more elegant way within one run of the
model.

Thanks,
Jeff

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Your question is (completely) ill-posed.  What is your actual
model?  What you have said makes no sense at all as it stands.
(Minimal self-contained example .....)

     cheers,

         Rolf Turner

On 28/02/12 09:25, jeff_hawkes wrote:
> Hi all,
> Is it possible to model a function where the unknown parameter appears both
> in the fitted equation AND in the determination of other parameters?  E.g.
>
> y = a^2 + b/2 + k
>
> where a = 2/k  and b = k^2
>
> and the model needs to determine k?  I know this is a very simple equation
> (its just an example), the one I am modelling is much more complicated!
>
> k appears in the equation which the n.l.r model fits, but it also affects
> other parameters in the equation.  Please let me know if you know a way of
> achieving this.  I realise it is possible to set up a loop where the
> modelled value for k is fed back in to a and b, and the model is run again
-
> but it seems like there should be a more elegant way within one run of the
> model.