spdj=: [: ,./ [EMAIL PROTECTED] ]\ ]

   3 spdj i.7 4
0 1  2  3 12 13 14 15 24 25 26 27
4 5  6  7 16 17 18 19  0  0  0  0
8 9 10 11 20 21 22 23  0  0  0  0



----- Original Message -----
From: "Miller, Raul D" <[EMAIL PROTECTED]>
Date: Sunday, February 18, 2007 8:23 am
Subject: RE: [Jprogramming] Style and Literacy in APL

> June Kim 
> > I don't know much about APL so it is hard for me to understand
> > either of the functions. (the author's intention was showing SPD
> > being easier to comprehend, though)
> 
> I'm with you there.
> 
> Personally, if I were to implement SPD in J, I'd probably use:
> 
> spd=: [EMAIL PROTECTED] ,/\ ]
> 
> > Now, could anyone help me translating the function spd into J
> > (then I might easily translate SPREAD, too)?
> > 
> > (I temporarily put the pdf file for the paper on my server. I might
> > remove it in a couple of days. Get it from
> > http://agcns.com/p1-berry.pdf )
> 
> I think I've literally translated SPD as:
> 
> SPD=:4 :0
> ((1{f),*/0 2{f)$,1 0 2|:(f=.x,c%x,1)$,(c=.d+(x|x-(0{d=.$y)),0){.y
> )
> 
> Which, again, seems to match your translation (in a later
> email).
> 
> However:
>   3 (spd -: SPD) 3 4$'can you see '
> 1
>   3 (spd -: SPD) 6 4$'can you see'
> 0
> 
> I'm not sure if my translation is wrong or if SPD fails to satisfy
> its declared purpose.  My SPD fails, and I suspect that it shares
> this property with the original.  But I haven't proven to myself
> that my translation is perfect.
> 
> P.S. here's how I'd define APL's rho in J;
> 
>   rho=: $ :($,)
> 
> FYI,
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