On my Windows Vista system it returns an answer: > values <- list(x=10:30, y=c(23.85, 28.805, 28.195, 26.23, 25.005, 20.475, + 17.33, 14.97, 11.765, 8.857, 5.3725, 5.16, 4.2105, 2.929, 2.174, 1.25, 1.0255, + 0.612, 0.556, 0.4025, 0.173)) > y.max <- max(values$y) > model <- nls(y ~ SSlogis(x, asym, xmid, scal), data=values, algorithm="port", + start=c(asym=y.max, xmid=15, scal=-0.5), upper=c(y.max, Inf, Inf)) > model Nonlinear regression model model: y ~ SSlogis(x, asym, xmid, scal) data: values asym xmid scal 28.805 17.268 -2.223 residual sum-of-squares: 32.02
Algorithm "port", convergence message: relative convergence (4) > R.version.string # Vista [1] "R version 2.6.1 Patched (2007-12-06 r43610)" On Jan 4, 2008 9:45 AM, <[EMAIL PROTECTED]> wrote: > Full_Name: Hendrik Weisser > Version: 2.6.1 > OS: Linux > Submission from: (NULL) (139.19.102.218) > > > The following computation never finishes and locks R up: > > > values <- list(x=10:30, y=c(23.85, 28.805, 28.195, 26.23, 25.005, 20.475, > 17.33, 14.97, 11.765, 8.857, 5.3725, 5.16, 4.2105, 2.929, 2.174, 1.25, 1.0255, > 0.612, 0.556, 0.4025, 0.173)) > > y.max <- max(values$y) > > model <- nls(y ~ SSlogis(x, asym, xmid, scal), data=values, > > algorithm="port", > start=c(asym=y.max, xmid=15, scal=-0.5), upper=c(y.max, Inf, Inf)) > > This used to work with R version 2.5.1 patched. > The problem does _not_ occur if the parameter "scal=-0.5" in the nls call is > changed, e. g. to "scal=-0.6" or "scal=-0.4". > Simply calling "model <- nls(y ~ SSlogis(x, asym, xmid, scal), data=values)" > also works, but this does not use the upper bound for the asym parameter, > which > was the point. > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel > ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
