Following the Indomethicin example in Pinheiro & Bates, chapter 6, page 277 etc, coming to the following comand: fm2Indom.nlme <- update( fm1Indom.nlme, random = pdDiag(A1 + lrc1 + A2 ~ 1) ) debugging nlme gives the following output: Browse[1]> n debug: modelResid <- ~eval(model, data.frame(data, getParsNlme(plist, fmap, rmapRel, bmap, groups, beta, bvec, b, level, N)))[naPat] Browse[1]> n debug: ww <- eval(modelExpression[[2]], envir = nlEnv) Browse[1]> n Error: subscript out of bounds Here the fm1Indom.nlme object is calculated with a formula somewhat different from the one given in the text, because that gives convergence problems: fm1Indom.nlme <- nlme(fm1Indom.lis, random=pdDiag(A1+lrc1+A2+lrc2 ~ 1) , control=list(msMaxIter=1000, msVerbose=TRUE,niterEM=100, returnObject=TRUE)) The algorithm says it has not converged, although the tracing output multiple times indicate that the current solution is probably a solution. The summary of the obtained object is very close to that given in the book. Kjetil Halvorsen -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._