On Tue, 30 Jun 2020 13:53:10 +0200 Luigi Marongiu <marongiu.lu...@gmail.com> wrote:
> function(a, b, x) { > y = (a * x^2) / (b^2 + x^2) > return(y) > } Take a look at the examples in ?nls.lm. The first argument of the function must be the parameter list/vector; the rest of the arguments are passed from ... in nls.lm call. This is _unlike_ do.call, which can be used to "unpack" a list of arguments into function arguments. To make it more concrete, change your function to: function(par) (par$a * par$x^2) / (par$b^2 + par$x^2) Then it should work. -- Best regards, Ivan ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.