prod(0, 1:1000) ; 0 * Inf etc

G'day Martin,

On Mon, 21 Apr 2008 18:40:43 +0200

I think most of us would expect  prod(0:1000)  to return 0, and ...
... it does.

However, many of us also expect  
  prod(x1, x2)    to be equivalent to
  prod(c(x1,x2))
the same as we can expect that for min(), max(), sum() and such
members of the "Summary" group.

Many may also expect that prod(x) and prod(rev(x)) are equivalent.
Unfortunately, this does not hold in finite precision arithmetic:

prod(0:1000)

[1] 0

prod(1000:0)

[1] NA

prod(rev(0:1000))

[1] NA

It might be better to educate useRs on finite precision arithmetic
than trying to catch such situations.  Note, I am saying "better", not
"easier". :-)  

Cheers,
	
	Berwin