[Rd] density(), with argument of length 1 (PR#2593)

[John Maindonald]

> From p.dalgaard@biostat.ku.dk  Sat Mar  1 21:22:47 2003
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> To: u9801539@leonard.anu.edu.au
> Cc: r-devel@stat.math.ethz.ch, R-bugs@biostat.ku.dk
> Subject: Re: [Rd] density(), with argument of length 1 (PR#2593)
> From: Peter Dalgaard BSA <p.dalgaard@biostat.ku.dk>
> Date: 01 Mar 2003 11:22:48 +0100
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> u9801539@leonard.anu.edu.au writes:
> 
> > The following is from version 1.6.2 of R under Windows,
> > or 1.6.1 under Mac OSX/X11
> > 
> > > density(1)
> > Error in if (!(lo <- min(hi, IQR(x)/1.34))) (lo <- hi) || (lo <- abs(x[1])) ||  : 
> >         missing value where logical needed
> > 
> > I am not sure how this should be handled.
> 
> It comes from this bit of code:
> 
> > bw.nrd0
> function (x)
> {
>     hi <- sd(x)
>     if (!(lo <- min(hi, IQR(x)/1.34)))
>         (lo <- hi) || (lo <- abs(x[1])) || (lo <- 1)
>     0.9 * lo * length(x)^(-0.2)
> }
> 
> in which hi is NA if x has length 1. A pragmatic way out would seem to
> be to change the first line to 
> 
> hi <- if (length(x) > 1) sd(x) else 0
> 
> (and I wonder why the author didn't go all the way with the ||
> sneakiness and said
> 
>     (lo <- min(hi, IQR(x)/1.34)) ||
>         (lo <- hi) || (lo <- abs(x[1])) || (lo <- 1)

Note that two of the other three bandwith rules also require attention:
> bw.ucv(1)
Error in fmin(function(arg) f(arg, ...), lower, upper, tol) : 
        invalid xmin value
> bw.SJ(1)
Error in TDh(cnt, b, n, d) : NA/NaN/Inf in foreign function call (arg 5)

The remaining rule has:
> bw.nrd(1)
[1] NA
which is reasonable.









John Maindonald                     email : john.maindonald@anu.edu.au
Centre for Bioinformation Science,  phone : (6125)3473        
c/o MSI,                            fax   : (6125)5549 
John Dedman Mathematical Sciences Building (Building 27)
Australian National University
Canberra ACT 0200
Australia