Next, isn't c1 the same as c11?
I make silly little scripts like this and I run them in a new Jconsole and
then do T '' lots of times until I'm pretty sure they agree.
T=: 3 : 0
n=:1+?6
d=:1+?6
]D=:(n%2) > (?]) n$d
]E=:?(n,d)$2
]c1=:0= ? A=:(2$d)$(>. d%2)
]c11=:?(d,d)$2
F=:($D)-:$E
G=:($c1)-:$c11
F,G
)
T ''
Linda
-----Original Mesesageh
From: [email protected]
[mailto:[email protected]] On Behalf Of Linda Alvord
Sent: Monday, November 05, 2012 5:12 AM
To: [email protected]
Subject: Re: [Jprogramming] Arc consistency in J
I just began to ponder this thread. Do you think E is the same as D?
th
D=. (n%2) > (?]) n$d
E=. ?(n,d)$2
Linda
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Michal D.
Sent: Sunday, November 04, 2012 11:26 PM
To: [email protected]
Subject: Re: [Jprogramming] Arc consistency in J
> >> variables. In other words, if we specify the constraint x < y it
> >> looks like either x1 < x2 or x2 < x1 is sufficient to satisfy arc
> >> consistency. In other words, i think we should always use the
> >> symmetric closure of the constraint.
> >
> >> Does this sound valid to you?
> >
> > Unfortunately not. There are no values that can satisfy x1<x2 and
x2<x1.
> > If this was the case all csps would have no solutions
>
> I meant x1<x2 OR x2<x1
>
> So symmetric closure was the wrong term for me to use.
>
> But I think we want to be using intersection of the relationship with
> its inverse.
>
> Does that sound right to you?
>
Sorry I missed the or. Unfortunately not, I mean you can have a constraint
like that if you want but you don't have to have to in general. I think
we're dwelling on an implementation detail. They (wikipedia) must just have
the < constraint propagating both ways.
My brain is fried but I did hack together an ugly search procedure. You can
try it out on a sudoku puzzle if you want. For some reason I couldn't
generate it using the code you gave me. http://pastebin.com/2zPB4DBA
Maybe we can update the printf docs to say:
load 'format/printf'
http://www.jsoftware.com/help/jforc/input_and_output.htm
Cheers,
Mike
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