Dear R colleagues,
I'm looking for some examples or vignettes or similar to suggest good ways to convert an
expression to a function. In particular, I'd like to (semi-) automate the conversion of
nls() expressions to residual functions. Example
Given variables y, T and parameters b1, b2, b3 in
exprtext<-"y~b1/(1+b2*exp(-b3*T))"
I'd like to generate a function
resids<-function(b, y, T){
b1<-b[1]
b2<-b[2]
b3<-b[3] # Pedestrian but hopefully clear
res<-b1/(1+b2*exp(-b3*T))-y
return(res)
}
Preferably, I want to use only R facilities rather than call Perl or Python etc. And as
much as possible, I'd like to automate the process. There are likely several ways to proceed.
Please contact me off list. I will report my success or lack thereof to the list in the
near future.
Thanks,
John Nash
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