I don't expect floating answers to be exact.  However, most of my
use of computers begins with inexact numbers, so getting the floating
routines as good as possible seems like a worthy effort to me.

Unfortunately, I stopped my reseach when J's answers went very
wrong at H 9.  Nars also supports extended percision and rational
numbers, so I've continued the work.  While it does well though 12, it
goes horribly wrong at 13.

   http://home.comcast.net/~paul.l.jackson/PLJsAPL/JandNars.txt

Paul

On Mon, Jun 18, 2012 at 7:01 PM, Roger Hui <[email protected]> wrote:
> Don't you become even a bit suspicious when the answers don't agree?
> Consider the number on the lower right hand corner:
>
> PLJsAPL:     2815820646.25489
> Dyalog:      2815825985
> NARS2000:    2815820182
> J Rational:  2815827300 (true answer).
>
> If you are proud of implementation X, I can bring it down to earth real
> quick by asking it to invert H 2*n, or by working in rational numbers.
>
>   H=: %@>:@(+/~)@i.
>   (+/ .* %.) H 20x
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