I recently started using R 2.7.2, and noticed a surprising change in
the behavior of var() on NA data:
R 2.6.1 (Patched), 2007-11-26, svn.rev 43541, x86_64-unknown-linux-gnu:
> stdev(rep(NA,3), na.rm=F)
[1] NA
> stdev(rep(NA,3), na.rm=T)
[1] NA
> var(rep(NA,3), na.rm=T, use="complete.obs")
[1] NA
R 2.7.2 (Patched), 2008-09-02, svn.rev 46491, x86_64-unknown-linux-gnu:
> stdev(rep(NA,3), na.rm=F)
[1] NA
> stdev(rep(NA,3), na.rm=T)
Error in var(x, na.rm = na.rm) : no complete element pairs
Enter a frame number, or 0 to exit
1: stdev(rep(NA, 3), na.rm = T)
2: var(x, na.rm = na.rm)
Selection: 0
> var(rep(NA,3), na.rm=T, use="complete.obs")
Error in var(rep(NA, 3), na.rm = T, use = "complete.obs") :
no complete element pairs
Is this change intentional? Also, what is causing it? Looking, I see
no changes in var() at all, so the new behavior must be due to a
change in what this call does:
.Internal(cov(x, y, na.method, FALSE))
The R 2.7.2 cov() also has this weird line:
else if (na.method != 3L) {
Note the "L" in the "3L". A typo? The older 2.6.1 cov() just has "3"
on that line, no "L".
Interactively redefining cov() to remove the "L" makes no difference in my
var() calls, but that could b
The original source file seems to be:
src/library/stats/R/cor.R
svn annotate says that 3L line was last changed nearly a year ago, way
back in rev 43302:
------------------------------------------------------------------------
r43302 | ripley | 2007-10-29 14:50:18 -0400 (Mon, 29 Oct 2007) | 2 lines
make cor/cov a little less inconsistent
The strange 3L line occurs twice in that file, in both cor() and cov():
$ grep -n 3L cor.R
36: else if (na.method != 3L) {
118: else if (na.method != 3L) {
That line might not be the cause of my "no complete element pairs"
problem (I'm not at all sure), but it does look suspicious.
--
Andrew Piskorski <[EMAIL PROTECTED]>
http://www.piskorski.com/
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