[R] self-starter functions for y = a + b * c^x

[Peter Ehlers]

On 2012-08-14 00:09, Christof Kluß wrote:
> Hi
>
> there are some predefined self-start functions, like SSmicmen, SSbiexp,
> SSasymp, SSasympOff, SSasympOrig, SSgompertz, SSflp, SSlogis, SSweibull,
> Quadratic, Qubic, SSexp (nlrwr)
>
> Btw, do you know graphic examples for this functions?
>
> The SSexpDecay (exponential decay) for y = (y0 - plateau)*exp(-k*x) +
> plateau from
> http://stats.stackexchange.com/questions/17126/how-can-i-make-my-r-nls-model-more-stable
> works fine, too.
>
> But now I search a self-starter for y = a + b * c^x
>
> Do you know a package that implement such self-starter or is there a
> easy way to do it myself?

Can't you just reparameterize with  c^x = exp(x * log(c)) ?

Peter Ehlers

>
> thx
> Christof