"Ing. Marek Brabec PhD" <[EMAIL PROTECTED]> writes: > dear list, > I am wondering if one can find examples and/or more detailed > descriptions of modifications needed when going beyond standard > corStruct classes (i.e. those already provided for use in lme/nlme)? > When I looked at pages 238-239 of Pinheiro/Bates (2000): Mixed-effects > models in S and S-plus, I found that I would need a bit more explicit > guidance what to do for implementing a new correlation structure than > that presented there. > I am thinking e.g. of random walk as of a non-stationary example > corStruct to implement. > Thanks for any help and/or pointing me to a source of general instructions. > All the Best > Marek Brabec
Hi Marek, I don't think there is any better way than to try deciphering and modifying an existing cor-class. Notice that there is a handful of methods to be dealt with, like these for the compund symmetry case > ls(pattern=".*corCompSymm", environment(gls)) [1] "Initialize.corCompSymm" "coef.corCompSymm" "coef<-.corCompSymm" [4] "corCompSymm" "corMatrix.corCompSymm" "recalc.corCompSymm" [7] "summary.corCompSymm" You might want to start off trying your hand by writing your own variance class. This is somewhat easier since preexisting ones are generally written in R whereas corClasses have .C calls inside. -p -- O__ ---- Peter Dalgaard Ă˜ster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html