Linda, stick to integer arithmetic:
   5 (0=[:?~#) 8
0 0 0 0 0 0 1 0
1 0 0 0 0 0 0 0
0 0 1 0 0 0 0 0
0 0 0 1 0 0 0 0
0 0 0 0 0 1 0 0
- Bo




>________________________________
> Fra: Linda Alvord <lindaalv...@verizon.net>
>Til: programm...@jsoftware.com 
>Sendt: 10:10 torsdag den 8. november 2012
>Emne: Re: [Jprogramming] Arc consistency in J
> 
>   ee=:(]%2) > ?~@$
>   ee
>0.5 > ?~@$
>   ff=: 13 :'0.5 > ?~x$y'
>   ff
>0.5 > [: ?~ $
>   5 ff 8
>0 0 0 0 1 0 0 0
>0 0 0 0 0 0 0 1
>0 0 0 0 1 0 0 0
>0 1 0 0 0 0 0 0
>0 0 1 0 0 0 0 0
>
>J is so smart, it eliminate the need for  *  
>
>   hh=: 13 :' ?~x$y'
>   hh
>[: ?~ $
>   ]A=:5 hh 8
>4 7 1 6 0 5 3 2
>4 2 3 1 5 7 0 6
>7 3 5 4 1 2 6 0
>5 3 2 4 1 7 6 0
>2 5 4 0 3 6 7 1
>   0.5 > A
>0 0 0 0 1 0 0 0
>0 0 0 0 0 0 1 0
>0 0 0 0 0 0 0 1
>0 0 0 0 0 0 0 1
>0 0 0 1 0 0 0 0
>      
>Mind boggling!
>
>Linda
>
>
>-----Original Message-----
>From: programming-boun...@forums.jsoftware.com
>[mailto:programming-boun...@forums.jsoftware.com] On Behalf Of Devon
>McCormick
>Sent: Wednesday, November 07, 2012 12:56 PM
>To: J-programming forum
>Subject: Re: [Jprogramming] Arc consistency in J
>
>At first glance, I thought the right tine of this fork
>   (2 %~ ]) > [: (? ]) $
>could be replaced by an idiom I frequently use
>   (?@$)
>but then realized that what we need is
>   (?~@$)
>so "dd" can be written as
>   (]%2) > ?~@$
>
>
>On Wed, Nov 7, 2012 at 1:31 AM, Michal D. <michal.dobrog...@gmail.com>wrote:
>
>> Thanks Roger, that makes sense now.  The history of J is one of it`s 
>> intriguing aspects for sure.
>>
>> Re: Linda: I would call it a v(erb) as opposed to a N(oun).  But what 
>> do I know? ;-)
>>
>> Mike
>>
>> On Tue, Nov 6, 2012 at 8:53 AM, Roger Hui <rogerhui.can...@gmail.com>
>> wrote:
>>
>> > 'noun verb verb' is a fork and is interpreted as 'noun"_ verb verb'
>> (noun"_
>> > is a constant verb whose result is noun).  
>> > http://keiapl.org/anec/#nvv
>> >
>> > 'verb verb noun' can not be made into a fork because 'verb noun' 
>> > already has an interpretation (*viz*., apply verb to noun).
>> >
>> >
>> > On Tue, Nov 6, 2012 at 8:47 AM, Michal D. 
>> > <michal.dobrog...@gmail.com
>> > >wrote:
>> >
>> > > > Change from a Noun to a verb, view its tacit version and apply 
>> > > > it to
>> > > data:
>> > > >
>> > > >     dd=: 13 :'(y%2) > (?]) x$y'
>> > > >
>> > > >     dd
>> > > > (2 %~ ]) > [: (? ]) $
>> > > >
>> > >
>> > > That is quite cool.  I'm surprised that you can automatically get 
>> > > the
>> > tacit
>> > > definition.  Does this work for any explicitly defined verb?
>> > >
>> > > I'm also surprised at the way %~ came out.  Do left hand arguments 
>> > > not require a & to bind the argument?  It is strange to me that 
>> > > (1) works
>> but
>> > > (2) does not.  It seems to me that (3) is the logical way to 
>> > > phrase
>> > either
>> > > of them (ie. a fork with a constant right / left side).  To 
>> > > reiterate,
>> > why
>> > > does (1) work?
>> > >
>> > > (1)    (2 %~ ]) > [: (? ]) $
>> > > (2)    (] % 2) > [: (? ]) $
>> > > (3a)   (2: %~ ]) > [: (? ]) $
>> > > (3b)   (] %~ 2:) > [: (? ]) $
>> > > (4a)   (%&2 ]) > [: (? ]) $      NB. incorrect (hook caught me out
>> > again)!
>> > > (4b)   ([: %&2 ]) > [: (? ]) $   NB. correct
>> > >
>> > > Cheers,
>> > >
>> > > Mike
>> > > ------------------------------------------------------------------
>> > > ---- For information about J forums see 
>> > > http://www.jsoftware.com/forums.htm
>> > >
>> > --------------------------------------------------------------------
>> > -- For information about J forums see 
>> > http://www.jsoftware.com/forums.htm
>> >
>> ----------------------------------------------------------------------
>> For information about J forums see http://www.jsoftware.com/forums.htm
>>
>
>
>
>--
>Devon McCormick, CFA
>^me^ at acm.
>org is my
>preferred e-mail
>----------------------------------------------------------------------
>For information about J forums see http://www.jsoftware.com/forums.htm
>
>----------------------------------------------------------------------
>For information about J forums see http://www.jsoftware.com/forums.htm
>
>
>
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