[Jprogramming] Use of (@) 'Atop'

[Raul Miller]

http://www.jsoftware.com/help/release/random.htm#scode

Thanks,

-- 
Raul


On Thu, Jul 7, 2016 at 8:37 AM, Martin Kreuzer <info at airkreuzer.com> wrote:
> Hi all -
>
> Approximating Pi using the Monte Carlo method (circle enscribed in unit
> square) came up with
>
>    pia=. 13 : '(4 * y %~ +/ 1 >: +/ *: <: +: ? (2,y) $ 0)'("0)
>    (pia 10^(4+i.3)) ,:(4+i.3)
> 3.1524 3.1438 3.14106
>      4      5       6
>
> I then compared my version with the J verb at Rosetta Code and the only
> difference I found was the use of 'Atop':
>
> piMC=: monad define "0
>    4* y%~ +/ 1>: %: +/ *: <: +: (2,y) ?@$ 0
> )
>
> Q:
> What is the advantage (in this particular case) of using 'Atop'..?
>    ? (2,y) $ 0
> vs
>    (2,y) ?@$ 0
>
> Thanks
> -M
>
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