search for: datplot

...rence lines for each panel. How do I index the current panel to chose the right reference vector value ? dat<-data.frame(id=rep(c("a","b","c"),4),val=1:12,quand=rep(c("t1","t2","t3","t4"),each=3)) ref<-c(10,8,6) plot.new() datplot<-dotplot(val~quand|id,data=dat,panel=function(...){ panel.dotplot(...) panel.abline(h=ref) }) print(datplot)

...impossible or very simple. I am attempting to fit a non-linear model to some measured data. One term in the model contains a square-root, but in the course of regression, this term turns negative and an error occurs. I started using Micrsoft's Excel Solver, and then I turned to NIST's Datplot statistical package. I can constrain in Solver, but it violates those constraints. :) Dataplot does not have the capability to constrain parameters. Does R have the capability to constrain or bound parameters in non-linear regressions? Thanks, Mark Davis