Hello. I am trying to understand the syntax of the nonlinear least
squares function (nls) when the function definition is made outside of
the call. Here is the context.
1. If I specify the following command, it works fine:
> fit2<-nls(
+ A~Am*(1-exp(-alpha*(I-LCP))),data=dat1,
+ start=list(Am=3.6,alpha=0.01,LCP=20))
2. Now, I want to be able to specify the function definition
outside of nls. I do the following:
> Mitscherlich<-function(Am,alpha,I,LCP,...){
Am*(1-exp(-alpha*(I-LCP)))
}
and then:
> fit3<-nls(
+ A~Mitscherlich,data=dat1,
+ start=list(Am=2.7,alpha=0.006,LCP=45))
and I get the error message: Error in lhs - rhs : non-numeric argument
to binary operator
What am I doing wrong?
Thanks.
Bill Shipley
Subject Matter Editor, Ecology
North American Editor, Annals of Botany
Département de biologie, Université de Sherbrooke,
Sherbrooke (Québec) J1K 2R1 CANADA
[EMAIL PROTECTED]
<http://callisto.si.usherb.ca:8080/bshipley/>
http://callisto.si.usherb.ca:8080/bshipley/
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