[R] step factor below minimum

[Kari Ruohonen]

I am trying to fit the 4-parameter logistic model with SSfpl. The
estimation is terminated with a message "step factor 0.000488281 reduced
below 'minFactor' of 0.000976562". I tried to change the minFactor with
nls.control(minFactor=yy)  with no apparent success. A call of
nls.control() without arguments always shows the value of 0.000976562.
Also the estimation terminates as previously although I tried to use
control=nls.control(minFactor=yy) option. Is there a way to get around
this or does this mean that my model is not estimable with R?

I am running Debian unstable i386 and R 1.3.0.

Thanks,

Kari

----------------------------------------------
Kari Ruohonen
Finnish Game and Fisheries Research Institute
Socioeconomic and Aquaculture Research

Turku Game and Fisheries Research
Itäinen Pitkäkatu 3, 20520 Turku, Finland
tel. +358-20-5751681, +358-40-5238321 (mobile)
fax  +358-20-5751689

http://www.rktl.fi


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