Hi fellow R-users,
I am (attempting) to take a formula object, and convert it into a
function which I can feed into optim. Basically, I have several
functions that fit the formula object to data, and analyze the
results. The next step would be to combine the fitting function
coefficient results and formula object into a function, which can be
passed to optim.
So, I am looking for a method, set of methods, or package(s) that are
designed to do this process. So far, I have had no luck in
determining any easy ways to resolve this issue, other than stringing
together a string, and using eval(parse"string").
Example:
formula<-as.formula(y~ (x1+x2)^2 + I(x1^2)+I(x2^2))
# becomes
func(x)<-function{coef[1] + coef[2]*x[1] + coef[3]*x[2]+
coef[4]*x[1]^2+coef[5]*x[2]^2 +coef[6]*x1*x2}
#where coef is a vector containing the fitted coefficient values.
Any ideas?
Corey
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