[R] Error in plotting non-linear regression

[Peter Ehlers]

On 2010-04-22 11:09, Muhammad Rahiz wrote:
> Hello everyone,
>
> I'm trying to draw the non-linear regression curve to look at the
> distance decay relationship between distance and correlation values. But
> I'm not able to plot the curve as I'm struggling with the following
> error ("parameters without starting value in 'data': x") and found no
> answers online.*
>
> *Can anyone help...
>
> --
> Muhammad*
>
>
> * s1 cm
> 1 0 0.57223196
> 2 10 0.33110049
> 3 20 0.11163181
> 4 30 0.10242237
> 5 40 0.09254315
> 6 50 0.02739370
> 7 60 0.02567137
> 8 70 0.02492397
> 9 80 0.03206637
> 10 90 0.02487381
> 11 100 0.01747584
> 12 110 0.15977533
> 13 120 0.13317708
>
> new <- data.frame(s1,cm)
> plot(s1,cm)
> f <- function(x,a,b){a*exp(-b*x)} fm <-
> nls(cm~f(x,a,b),data=new,start=c(a=1,b=1)) co <- coef(fm)

Presumably you want f(s1,a,b) in your nls call.

  -Peter Ehlers

> curve(f(x,a=co[1],b=co[2]),add=TRUE,col="blue")
>
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-- 
Peter Ehlers
University of Calgary