[R] Is DUD available in nls()?

Ben Bolker bbolker at gmail.com
Tue Apr 2 09:22:33 CEST 2013

Bert Gunter <gunter.berton <at> gene.com> writes:

> I certainly second all Jeff's comments.
> **HOWEVER** :
> http://www.tandfonline.com/doi/pdf/10.1080/00401706.1978.10489610
> IIRC, DUD's provenance is old, being originally a BMDP feature.

  If you want to do derivative-free nonlinear least-squares fitting
you could do something like:

dnorm2 <- function(x,mean,log=FALSE) {
   ssq <- sum((x-mean)^2)
   n <- length(x)

  This is not necessarily the most efficient/highly tuned possibility,
but it is one reasonably quick way to get going (you can substitute
other derivative-free optimizers, e.g.


(I think).

  This isn't the exact algorithm you asked for, but it might serve
your purpose.

  Ben Bolker

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