Hi, I am trying to bootstrap the difference between each parameters among two non linear regression (distributed loss model) as following:
# data.frame > Raies[1:10,] Tps SolA Solb 1 0 32.97 35.92 2 0 32.01 31.35 3 1 21.73 22.03 4 1 23.73 18.53 5 2 19.68 18.28 6 2 18.56 16.79 7 3 18.79 15.61 8 3 17.60 13.43 9 4 14.83 12.76 10 4 17.33 14.91 etc... # non linear model (work well) RaiesLossA.nls<-nls(SolA~a/(1+b*Tps)^c,start=c(a=32,b=0.5,c=0.6)) RaiesLossB.nls<-nls(Solb~a/(1+b*Tps)^c,start=c(a=33,b=1.5,c=0.5)) # bootstrap library(boot) dif.param<-function(data,i){ RaiesLossA.nls<-nls(SolA[i]~a/(1+b*Tps[i])^c,start=c(a=31,b=0.5,c=0.6)) RaiesLossB.nls<-nls(Solb[i]~a/(1+b*Tps[i])^c,start=c(a=33,b=1.4,c=0.5)) RaiesLossA.nls$m$getPars()-RaiesLossB.nls$m$getPars() } > myboot<-boot(Raies,dif.param,R=1000) Error in numericDeriv(form[[3]], names(ind), env) : Missing value or an Infinity produced when evaluating the model It seems that the init values (start=) may come not to be suitable while bootstraping. Data can be sent offline to whom wanted to try on the dataset. Any hint welcome! Best regards, Patrick Giraudoux University of Franche-Comté Department of Environmental Biology EA3184 af. INRA F-25030 Besançon Cedex tel.: +33 381 665 745 fax.: +33 381 665 797 http://lbe.univ-fcomte.fr ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html