On Mon, Feb 14, 2011 at 5:17 PM, Devon McCormick <[email protected]> wrote:

> I was enjoying Chris Burke's 1996 essay on "Elegant Programming" -
> http://www.jsoftware.com/papers/elegant.htm - but when I tried some of his
> examples, one did not work.  The elegant derivation for harmonic mean from
> arithmetic mean:
>
>   am=. +/ % #
>   hm=. am &. %
>
> When "hm" is used on the argument "2 3 5" as shown in the essay, it returns
> the input instead of the answer "2.9032258".  A little investigation
> uncovered that the definition of harmonic mean in contemporary J should be
>
>   hm=. am &. (%"_)
>

Or use &.:

But, yes, language drift is hard on reference works.

-- 
Raul
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