Displaying 1 result from an estimated 1 matches for "nlstoyproblem".
2008 May 23
3
nls diagnostics?
Hi, All:
What tools exist for diagnosing singular gradient problems with
'nls'? Consider the following toy example:
DF1 <- data.frame(y=1:9, one=rep(1,9))
nlsToyProblem <- nls(y~(a+2*b)*one, DF1, start=list(a=1, b=1),
control=nls.control(warnOnly=TRUE))
Error in nlsModel(formula, mf, start, wts) :
singular gradient matrix at initial parameter estimates
This example is obviously stupid, but other singular gradient
problems are not so...