Dear List, The gbm package on Win 7 produces different results for the relative importance of input variables in R 32-bit relative to R 64-bit. Any idea why? Any idea which one is correct?
Based on this example, it looks like the relative importance of 2 perfectly correlated predictors is "diluted" by half in 32-bit, whereas in 64-bit, one of these predictors gets all the importance and the other gets none. I found this interesting. ### Sample code library(gbm) set.seed(12345) xc=matrix(rnorm(100*20),100,20) y=sample(1:2,100,replace=TRUE) xc[,2] <- xc[,1] gbmfit <- gbm(y~xc[,1]+xc[,2] +xc[,3], distribution="gaussian") summary(gbmfit) ### Results on R 2.12.0 (32-bit) var rel.inf 1 xc[, 3] 49.76143 2 xc[, 1] 27.27432 3 xc[, 2] 22.96425 > ### Results on R 2.12.0 (64-bit) > summary(gbmfit) var rel.inf 1 xc[, 1] 50.23857 2 xc[, 3] 49.76143 3 xc[, 2] 0.00000 Thanks, Axel. [[alternative HTML version deleted]] ______________________________________________ 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.