Hi Everyone, This example code results in R 'crashing'; that is the R application closes with no warnings or error messages. #----------------------- myD <- read.table(stdin(), header=TRUE, nrows=20) Broth Salt pH Temp N Y Growth 1 310 9.0 2.92 10 90.0 NA 0 2 615 6.0 7.82 30 1.0 2 1 3 217 2.0 7.34 10 7.0 8 1 4 338 10.0 4.44 10 90.0 NA 0 5 240 4.0 7.33 10 20.0 21 1 6 336 10.0 3.90 10 90.0 NA 0 7 279 7.0 6.73 10 90.0 NA 0 8 1021 9.0 5.03 45 8.0 9 1 9 974 7.0 4.01 45 90.0 NA 0 10 265 7.0 2.93 10 90.0 NA 0 11 934 4.0 5.28 45 0.1 1 1 12 669 9.0 5.03 30 90.0 NA 0 13 875 10.0 6.24 37 1.0 2 1 14 385 2.0 5.84 20 1.0 2 1 15 562 2.0 5.84 30 0.1 1 1 16 718 0.5 5.54 37 0.1 1 1 17 845 9.0 5.03 37 3.0 6 1 18 913 2.0 5.84 45 0.1 1 1 19 577 4.0 4.10 30 90.0 NA 0 20 20 0.5 7.44 8 24.0 27 1
library(rpart) library(survival) fit<-rpart(Surv(N,Y,type="interval2")~Salt+pH+Temp, data=myD) #--------------------- Professor Ripley helpfully pointed out that the documentation does not say that interval censoring is supported, and indeed this seems only to happen with interval censored data. ?rpart indicates that the dependent variable may be a survival object. Neither ?rpart nor "An Introduction to Recursive Partitioning Using the RPART Routines" (Therneau et al 1997) suggest that the dependent variable may contain interval censored data, but neither do they suggest it shouldn't; i.e. as far as I'm aware (!) this restriction is not documented. This post has three purposes: 1) Bring this behaviour - especially the crash in response to 'bad' data - to the attention of the authors. 2) Seek an explanation of the restriction (if intentional). In my simplicity, it seems that interval censored data should be easier to handle than left or right censored - after all the information content is greater. 3) Seek guidance on how to work around the problem. I'm minded to replace the interval censored data by the mid points of the intervals. Does anyone have any comments on such an approach? Any comments gratefully received. Keith Jewell ========================================== Version: platform = i386-pc-mingw32 arch = i386 os = mingw32 system = i386, mingw32 status = Patched major = 2 minor = 8.1 year = 2009 month = 01 day = 07 svn rev = 47502 language = R version.string = R version 2.8.1 Patched (2009-01-07 r47502) Windows Server 2003 x64 (build 3790) Service Pack 2 Locale: LC_COLLATE=English_United Kingdom.1252;LC_CTYPE=English_United Kingdom.1252;LC_MONETARY=English_United Kingdom.1252;LC_NUMERIC=C;LC_TIME=English_United Kingdom.1252 Search Path: .GlobalEnv, package:stats, package:graphics, package:grDevices, package:utils, package:datasets, package:methods, Autoloads, package:base ______________________________________________ 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.
