problem with nls starting values

now I feel very silly! I swear I was trying this for a long time and it 
didn't work. Now that I closed R and restarted it it works also on my 
machine.

So is the only problem that my model is overparametrized with the data I 
have? however shouldn't it be possible to fit an nls to these data?

thanks for the help

Am 27.09.2012 21:27, schrieb Berend Hasselman:

y_val<-115-118*exp(-0.12*(seq(1,100)+rnorm(100,0,0.8)))

x_val<-seq(1:100)
plot(y_val~x_val)
summary(mod1<-nls(y_val~a-b*exp(-c*x_val),start=list(a=115,b=118,c=0.12)))

Benedikt Gehr
Ph.D. Student

Institute of Evolutionary Biology and Environmental Studies
University of Zurich
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