Hello list, I'm trying to fit a model like beta[trt]/(1+alpha*x) where the data include some grouping factor. The problem is that the estimate for alpha is undefined for some of the treatments - any value greater than 20 is equally good and a step function would suffice. Ignoring the grouping structure, I can fit this using nls with the port algorithm by restricting the upper value of alpha to 20. Is there a way to do something similar in nlme?
Thanks! Manuel -- http://mutualism.williams.edu ______________________________________________ R-help@r-project.org mailing list 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.
