[Rd] Something strange in cor.test in R-1.8.0 (PR#4718)
Peter Dalgaard
p.dalgaard at biostat.ku.dk
Thu Oct 23 13:44:45 MEST 2003
Kurt Hornik <Kurt.Hornik at wu-wien.ac.at> writes:
> >>>>> maechler writes:
>
> >>>>> "Duncan" == Duncan Murdoch <dmurdoch at pair.com>
> >>>>> on Wed, 22 Oct 2003 08:17:32 -0400 writes:
>
> Duncan> I've now tried the code
>
> > set.seed(1)
> > x <- rnorm(50)
> > y <- rnorm(50)
> > cor.test(x,y,method="spearman")
> > x <- rnorm(50)
> > y <- rnorm(50)
> > cor.test(x,y,method="spearman")
>
> Duncan> in r-patched (which gives apparently correct results), and r-devel,
> Duncan> which gives the first result correct, the second incorrect; when
> Duncan> repeated, both are bad.
> > Hmm,
> > funny.
>
> > I get repeatable results in in R 1.7.1 , 1.8.0, R-patched and
> > R-devel (all on Linux),
>
> > with an (ugly but convenient) 1-liner :
>
> >> set.seed(1); for(k in 1:2){x <- rnorm(50);y <- rnorm(50);print(unlist(cor.test(x,y,method="spearman")[1:4]))}
> > statistic.S p.value estimate.rho
> > 23640.0000000 0.3482088 -0.1351741
> > statistic.S p.value estimate.rho
> > 1.724800e+04 2.322263e-01 1.717647e-01
>
> I get the same on Debian GNU/Linux.
>
> Where do we stand on this? Windows-specific?
Probably, but of a nasty kind which I think we need to get to the
bottom of. As I see it there are two possible causes
1. A bug in a Windows library or compiler. Potentially that could
affect everything else.
2. A bug in ctest that just happens only to cause visible damage on
Windows, but perhaps invisible damage elsewhere.
Either way, I think we need to investigate.
--
O__ ---- Peter Dalgaard Blegdamsvej 3
c/ /'_ --- Dept. of Biostatistics 2200 Cph. N
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907
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