Hi, This is essentially a reposting of http://tolstoy.newcastle.edu.au/R/devel/05/11/3305.html which had no responses, and the behaviour reported there persists in r-devel as of yesterday. (1) sort() with non-null partial
x = rnorm(100000) keep = as.integer(ppoints(10000) * 100000) system.time(sort(x))
[1] 0.05 0.00 0.04 0.00 0.00
system.time(sort(x, partial = keep))
[1] 52.04 0.02 52.08 0.00 0.00 This is perhaps not strictly a bug, but taking approximately 1000 times longer to do a subset of the work seems pointless at best. (2) quantile.default() always calls sort() with a non-null partial argument. Consequently,
system.time(quantile(x, ppoints(10000)))
[1] 88.82 0.05 88.90 0.00 0.00 There's no way around this except by writing a custom version of quantile. lattice currently does this, giving
system.time(lattice:::fast.quantile(x, ppoints(10000)))
[1] 0.07 0.01 0.08 0.00 0.00 Which brings me to my wishlist request: if (1) cannot be fixed easily, could quantile.default() at least have an optional argument that can be used to disable partial sorting?
sessionInfo()
Version 2.3.0 Under development (unstable) (2006-02-28 r37448) x86_64-unknown-linux-gnu attached base packages: [1] "methods" "stats" "graphics" "grDevices" "utils" "datasets" [7] "base" Deepayan -- http://www.stat.wisc.edu/~deepayan/