Going from tacit to explicit can be tricky. This is an example of a monadic
fork.
A=: ,</~i.5
f=: # i.@#
f A
1 2 3 4 7 8 9 13 14 19
g=: 13 :'y#i.#y'
g A
1 2 3 4 7 8 9 13 14 19
f
# i.@#
g
] # [: i. #
5!:4 <'f'
-- #
--+ -- i.
L- @ -+- #
5!:4 <'g'
-- ]
+- #
--+ -- [:
L---+- i.
L- #
Linda
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of 'Jon Hough'
via Programming
Sent: Saturday, September 26, 2015 11:06 PM
To: [email protected]
Subject: Re: [Jprogramming] Generate Complete Graphs
These are all great, thanks.
By the way, off-topic, in dissect it might be a good idea to use Courier or
a typeface with serifs. It is very easy to misread I. as |., at least for
me.
--------------------------------------------
On Sun, 9/27/15, Henry Rich < <mailto:[email protected]>
[email protected]> wrote:
Subject: Re: [Jprogramming] Generate Complete Graphs
To: <mailto:[email protected]> [email protected]
Date: Sunday, September 27, 2015, 11:21 AM
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: <mailto:[email protected]>
[email protected]
> [ <mailto:[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 <
<mailto:[email protected]> [email protected]> > wrote:
>> Enter
"comb" to see the tacit version of my verb:
>>
>> comb
>> ([ = [: +/"1 [: #: [: i. 2 ^ ])
([: |. [: I. #) [: #: [: i. 2 ^ ]
>>
>> Linda
>>
>> -----Original
Message-----
>> From: <mailto:[email protected]>
[email protected]
>> [ <mailto:[email protected]>
mailto:[email protected]]
On Behalf Of Linda A
>> Alvord
>> Sent: Saturday, September 26, 2015
11:48 AM
>> To: <mailto:[email protected]> [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: <mailto:[email protected]>
[email protected]
>> [ <mailto:[email protected]>
mailto:[email protected]]
On Behalf Of Henry
>> Rich
>> Sent: Saturday, September 26, 2015
11:12 AM
>> To: <mailto:[email protected]> [email protected]
>> Subject: Re: [Jprogramming] Generate Complete Graphs >> >> ; <@({. ,.
}.)\.@i. 5 >> >> >> >> (#~
</"1) (#: <mailto:i.@(*/))> 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
>>>
< <mailto:[email protected]> [email protected]>
>> wrote:
>>>
Subject: [Jprogramming] Generate Complete Graphs >>> To: "Programming
Forum" < <mailto:[email protected]> [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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>>>
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