Yes, that's very pretty.
Henry Rich
On 9/26/2015 10:08 PM, Linda A Alvord wrote:
Or:
5 5#:I.,</~i.5
0 1
0 2
0 3
0 4
1 2
1 3
1 4
2 3
2 4
3 4
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Raul Miller
Sent: Saturday, September 26, 2015 6:52 PM
To: Programming forum
Subject: Re: [Jprogramming] Generate Complete Graphs
Another variation might be:
require'stats'
complete=: 2&comb
That said, here's an illustration of why it can be easy to calculate:
-.+/\=i.5
0 1 1 1 1
0 0 1 1 1
0 0 0 1 1
0 0 0 0 1
0 0 0 0 0
5 5 #:I.,-.+/\=i.5
0 1
0 2
0 3
0 4
1 2
1 3
1 4
2 3
2 4
3 4
Making that concise and tacit will change its form, but hopefully the
underlying concept is clear?
Thanks,
--
Raul
On Sat, Sep 26, 2015 at 5:37 PM, Linda A Alvord <[email protected]>
wrote:
Enter "comb" to see the tacit version of my verb:
comb
([ = [: +/"1 [: #: [: i. 2 ^ ]) ([: |. [: I. #) [: #: [: i. 2 ^ ]
Linda
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Linda A
Alvord
Sent: Saturday, September 26, 2015 11:48 AM
To: [email protected]
Subject: Re: [Jprogramming] Generate Complete Graphs
comb=: 13 :'(x=+/"1 #:i.2^y) ([:|.[:I.#) #:i.2^y'
2 comb 5
0 1
0 2
0 3
0 4
1 2
1 3
1 4
2 3
2 4
3 4
3 comb 4
0 1 2
0 1 3
0 2 3
1 2 3
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Henry
Rich
Sent: Saturday, September 26, 2015 11:12 AM
To: [email protected]
Subject: Re: [Jprogramming] Generate Complete Graphs
; <@({. ,. }.)\.@i. 5
(#~ </"1) (#: i.@(*/)) 2 $ 5
Henry Rich
On 9/26/2015 9:24 AM, 'Jon Hough' via Programming wrote:
Sorry, the second verb should be
getEdges =: 3 : 0
if. 1 > # y do.
else.
h =. 1{.y
t =. 1}.y
((h&,)"0 t ), getEdges t
end.
)
(changed getNodes to getEdges)
--------------------------------------------
On Sat, 9/26/15, 'Jon Hough' via Programming
<[email protected]>
wrote:
Subject: [Jprogramming] Generate Complete Graphs
To: "Programming Forum" <[email protected]>
Date: Saturday, September 26, 2015, 10:16 PM
I have a couple of verbs to represent
a complete (undirected) graph as a list of edges. Clearly
there are "N choose 2" edges that need to be generated. This
is my code
complete =: 3 : 0
nodes =. i. y
getEdges nodes
)
getEdges =: 3 : 0
if. 1 > # y do.
else.
h =. 1{.y
t =. 1}.y
((h&,)"0 t ), getNodes t
end.
)
e.g. I can get the 10 edges of the graph K5 by doing
complete 5
My above code is ugly however. To be specific, it seems too
imperative for J, and the first part of the if. do. in
getEdges doesn't return anything which seems ugly.
I would like to know if there is a more J-like, terse way to
do this.
Regards,
Jon
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