[Rd] 0.45<0.45 = TRUE (PR#10744)
Barry Rowlingson
b.rowlingson at lancaster.ac.uk
Wed Feb 13 13:40:48 CET 2008
hadley wickham wrote:
> It's more than that as though, as floating point addition is no longer
> guaranteed to be commutative or associative, and multiplication does
> not distribute over addition. Many concepts that are clear cut in
> pure math become fuzzy in floating point math - equality, singularity
> of matrices etc etc.
I've just noticed that R doesn't calculate e^pi - pi as equal to 20:
> exp(pi)-pi == 20
[1] FALSE
See: http://www.xkcd.com/217/
Barry
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