[Jprogramming] A Tree Question

[Henry Rich]

Oh, I'm sorry, I've been working with & so much lately that I used its 
rank.  It should simply be

    ([: f g)"g <=> f at g

Henry Rich


On 12/21/2012 7:05 PM, Linda Alvord wrote:
> Henry, I can't make your suggestion work.
>     a
> 0 1 0 1 0 4
>     b
> 0 0 2 3 2 3
>     i=: 13 :'(=x) #@# y'
>     i
> ] #@#~ [: = [
>     a i b
> 3 2 1
>     NB.  ([: f g)"({. g b. 0) <=> f at g
>     k=: ] (([: # #)"({.# b. 0))~ [: = [
>     k
> ] ([: # #)"_~ [: = [
>     a k b
> 3
>
> What am I missing?
>
> Linda
>
> -----Original Message-----
> From: programming-bounces at forums.jsoftware.com [mailto:programming-bounces at forums.jsoftware.com] On Behalf Of Henry Rich
> Sent: Friday, December 21, 2012 1:52 PM
> To: programming at jsoftware.com
> Subject: Re: [Jprogramming] A Tree Question
>
> Writing J without @@: is like writing English without the letter 'e'.  I don't know what it shows, and it sounds funny, but look! I did it.
>
>      ([: f g) <=> f@:g
>      ([: f g)"({. g b. 0) <=> f at g
>
> Henry Rich
>
> On 12/21/2012 1:30 PM, Linda Alvord wrote:
>> So how can you write an equivalent explicit expression that will have the same result of g without  @ or @: ?
>>
>> -----Original Message-----
>> From: programming-bounces at forums.jsoftware.com
>> [mailto:programming-bounces at forums.jsoftware.com] On Behalf Of bob
>> therriault
>> Sent: Friday, December 21, 2012 1:02 PM
>> To: programming at jsoftware.com
>> Subject: Re: [Jprogramming] A Tree Question
>>
>>     Hi LInda,
>>
>> Since forks result in verbs of infinite rank (unless changed by the
>> rank conjunction), #@# is not actually equivalent to ([:##), although
>> #@:# is. Watch what happens when I swap @: for @
>>
>>    g=: 13 :'(=x) #@# y'
>>      a=:0 0 1 0 1 5
>>      b=:0 1 1 3 2 3
>>      a g b
>> 3 2 1
>>      g1=:13 :'(=x) #@:# y'
>>      a g1 b
>> 3
>>
>> Cheers, bob
>>
>> On 2012-12-21, at 9:51 AM, Linda Alvord wrote:
>>
>>> Why do the trees of  g  and  h appear to agree, but their results are
>>> not the same?
>>>
>>>
>>>
>>>      ]a=:?>:i.6
>>>
>>> 0 0 1 0 1 5
>>>
>>>     ]b=:?>:i.6
>>>
>>> 0 1 1 3 2 3
>>>
>>>     f=: 13 :'x#/.y'
>>>
>>>     f
>>>
>>> #/.
>>>
>>>     a f b
>>>
>>> 3 2 1
>>>
>>>     g=: 13 :'(=x) #@# y'
>>>
>>>     g
>>>
>>> ] #@#~ [: = [
>>>
>>>     a g b
>>>
>>> 3 2 1
>>>
>>>     NB. x u at v y ↔ u x v y
>>>
>>>     h=: 13 :'(=x) ([:##) y']
>>>
>>>     h
>>>
>>> (] ([: # #)~ [: = [) ]
>>>
>>>     a h b
>>>
>>> 3
>>>
>>>     5!:4 <'g'
>>>
>>>    ┌─ ]
>>>    │           ┌─ #
>>>    ├─ ~ ─── @ ─┴─ #
>>> ──┤
>>>    │     ┌─ [:
>>>    └─────┼─ =
>>>          └─ [
>>>
>>>     5!:4 <'h'
>>>
>>>        ┌─ ]
>>>        │          ┌─ [:
>>>        ├─ ~ ──────┼─ #
>>>    ┌───┤          └─ #
>>>    │   │     ┌─ [:
>>> ──┤   └─────┼─ =
>>>    │         └─ [
>>>    └─ ]
>>>
>>>     g
>>>
>>> ] #@#~ [: = [
>>>
>>>     h
>>>
>>> (] ([: # #)~ [: = [) ]
>>>
>>>
>>>
>>> Backtracking  i  and  j  are OK.
>>>
>>>
>>>
>>>    i=: 13 :'x #@# y'
>>>
>>>     i
>>>
>>> #@#
>>>
>>>     a i b
>>>
>>> 7
>>>
>>>     j=: 13 :'#x#y'
>>>
>>>     j
>>>
>>> [: # #
>>>
>>>     a j b
>>>
>>> 7
>>>
>>>     5!:4 <'i'
>>>
>>>        ┌─ #
>>> ── @ ─┴─ #
>>>
>>>     5!:4 <'j'
>>>
>>>    ┌─ [:
>>> ──┼─ #
>>>    └─ #
>>>
>>>
>>>
>>> I have tried to include rank of the verbs but I haven’t found the
>>> right combination if that is what is necessary.
>>>
>>>
>>>
>>> Linda
>>>
>>> ---------------------------------------------------------------------
>>> - 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
>>
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
>
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
>