Hallo! I have a problem with fitting data with nls. The first example with y1 (data frame df1) shows an error, the second works fine.
Is there a possibility to get a fit (e.g. JMP can fit also data I can not manage to fit with R). Sometimes I also got an error singularity with starting parameters. # x-values x<-c(-1,5,8,11,13,15,16,17,18,19,21,22) # y1-values (first data set) y1=c(-55,-22,-13,-11,-9.7,-1.4,-0.22,5.3,8.5,10,14,20) # y2-values (second data set) y2=c(-92,-42,-15,1.3,2.7,8.7,9.7,13,11,19,18,22) # data frames df1<-data.frame(x=x, y=y1) df2<-data.frame(x=x, y=y2) # start list for parameters sl<-list( d=0, b=10, c1=90, c2=20) # y1-Analysis - Result: Error in ... singular gradient nls(y~d+(x-b)*c1*(x-b<0)+(x-b)*c2*(x-b>=0), data=df1, start=sl) # y2-Analysis - Result: working... nls(y~d+(x-b)*c1*(x-b<0)+(x-b)*c2*(x-b>=0), data=df2, start=sl) # plots to look at data par(mfrow=c(1,2)) plot(df1$x,df1$y) plot(df2$x,df2$y) Perhaps there is another fitting routine? Can anybody help? Best wishes, Karl ___________________________________________________________ Bestellen Sie Y! DSL und erhalten Sie die AVM "FritzBox SL" für 0€. Sie sparen 119€ und bekommen 2 Monate Grundgebührbefreiung. ______________________________________________ [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