Jacob Brogren <jacob <at> brogren.nu> writes: > > All, > > I rerun once again and managed to reproduce the results from the text book. > Made no changes to the code. Could > it be some problem with convergence?
It is possible, but *extremely* unlikely, to get non-deterministic results from R (i.e. running the same code twice from an identical state and getting different answers [run from a clean R session to be absolutely sure]) -- this only happens if there is a deep, C-level bug in the internals of the code, which is unlikely in a piece of core functionality like coxph(). It is slightly more likely, but still unlikely, that running the code changes the state of the R session in a subtle way that makes it run differently the second time in a row. By far the most likely situation is that you have made some minor change in the state (i.e. you redefined some variable) that allows the code to reproduce the results in the book. (I know I've done this many times, even when I was initially fairly certain that I hadn't changed anything.) In defense of Crawley: he's written a book that is very useful to a lot of R users, even if advanced R users sometimes find it a bit sloppy in places. I agree that he hasn't contributed much back to the community (except for helping a large population of beginning users to learn how to use R, which is non-trivial), but I don't think he has gone out of his way to claim any kind of official status (other than calling his book "The R Book"). Ben Bolker ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
