Maria Salomé Esteves Cabral
2007-May-14 16:30 UTC
[R] Nonlinear Mixed-Effects Models (DNase)
Hi! I tried to fit four-parameter logistic model (SSfpl) to DNase data based on log(conc) (mixed model) but I never get convergence. Can anyone help me? Thanks Salom?
Hi How did you try to fit the model? library(nlme)> DNase$lconc<-log(DNase$conc) > head(DNase)Grouped Data: density ~ conc | Run Run conc density lconc 1 1 0.04882812 0.017 -3.0194489 2 1 0.04882812 0.018 -3.0194489 3 1 0.19531250 0.121 -1.6331544 4 1 0.19531250 0.124 -1.6331544 5 1 0.39062500 0.206 -0.9400073 6 1 0.39062500 0.215 -0.9400073> DNase<-groupedData(density~lconc|Run, data=DNase) > fit<-nlsList(density~SSfpl(lconc, A,B, xmid, scal), data=DNase) > fit1<-nlme(fit)> fixef(fit)A B xmid scal 0.0321532 2.3585764 1.4207304 1.0132287> ranef(fit)A B xmid scal 10 0.0052970445 -0.14330145 -0.111382663 0.033117245 11 -0.0156166995 0.05346347 0.095989293 0.097123510 9 -0.0136680461 -0.12703714 -0.102259590 0.004734638 1 -0.0400504359 0.01866298 0.086672974 0.049350211 4 -0.0344644982 -0.02109811 0.022589390 -0.009372415 8 0.0133393611 -0.16099322 -0.111791065 -0.078766236 5 -0.0122056683 -0.12938379 -0.119769285 -0.047167443 7 0.0320448897 0.02841489 0.079210580 0.045662102 6 0.0467424320 -0.01338672 -0.001926885 -0.023503062 2 -0.0009855356 0.12535679 -0.027580167 -0.081603650 3 0.0195671562 0.36930228 0.190247418 0.010425101>works. Regards Petr petr.pikal at precheza.cz r-help-bounces at stat.math.ethz.ch napsal dne 14.05.2007 18:30:58:> Hi! > > I tried to fit four-parameter logistic model (SSfpl) to DNase databased on> log(conc) (mixed model) but I never get convergence. Can anyone help me?> > Thanks > > Salom? > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guidehttp://www.R-project.org/posting-guide.html> and provide commented, minimal, self-contained, reproducible code.