Earl F. Glynn <efg <at> stowers-institute.org> writes: > > It's not clear to me why this problem cannot be "fixed" somehow. You
You might try optim instead of nls, which always (well, as far I used it) converges. However, resulting coefficients may be totally off, and you should use profiling to check the reliability. Dieter ______________________________________________ R-help@stat.math.ethz.ch 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.