But can you explain the difference in a few words?

-----Original Message-----
From: programming-boun...@forums.jsoftware.com 
[mailto:programming-boun...@forums.jsoftware.com] On Behalf Of Raul Miller
Sent: Saturday, July 19, 2014 9:15 PM
To: Programming forum
Subject: Re: [Jprogramming] High Speed Train Challenge

J's trace facility should make the answer to this question obvious?

Thanks,

-- 
Raul


On Sat, Jul 19, 2014 at 8:49 PM, Linda Alvord <lindaalv...@verizon.net> wrote:
> I'm still looking for the phrase or concept that explains the difference
> between these two.  Why are they producing different results?
>
>    3(***(***)(***))4
> 35831808
>
>   3((***)(***)***)4
> 429981696
>
>  If you grew up in the early years using APL, an idea might come to mind.
>
> Linda
>
> -----Original Message-----
> From: programming-boun...@forums.jsoftware.com
> [mailto:programming-boun...@forums.jsoftware.com] On Behalf Of 'Pascal
> Jasmin' via Programming
> Sent: Saturday, July 19, 2014 8:34 PM
> To: programm...@jsoftware.com
> Subject: Re: [Jprogramming] High Speed Train Challenge
>
>
>
> 3 * utu utu 4
>
>    3 * 1 : '[: u~ u' 1 : '[: u~ u' 4
> 429981696
>
>
>
> ----- Original Message -----
> From: Kip Murray <thekipmur...@gmail.com>
> To: "programm...@jsoftware.com" <programm...@jsoftware.com>
> Cc:
> Sent: Saturday, July 19, 2014 6:55:02 PM
> Subject: Re: [Jprogramming] High Speed Train Challenge
>
>    utu =: 1 : '[: u~ u'
>    3 *:@* utu 4
> 429981696
>
> uses the ideas that *** is equivalent to *:@* and u u u is equivalent to [:
> u~ u
>
> On Saturday, July 19, 2014, 'Pascal Jasmin' via Programming <
> programm...@jsoftware.com> wrote:
>
>> I'm not sure I'm arguing for the idea.  I've disliked ~ in the past
>> because I've read it as one of the other 2 meanings that was written.  I
>> wonder if making reflexive more common would help overcome forgetting it
>> exists quicker.
>>
>> from your examples, it would appear that good candidates for monadic + and
>> * would be +~ and *~.  Monadic * and + could have been chosen with +: and
>> *: symbols.  We can (fortunately) implement such bivalence ourselves:
>>
>> area =: *~
>>
>> area 8
>> 6 area 8
>>
>>
>> ----- Original Message -----
>> From: robert therriault <bobtherria...@mac.com <javascript:;>>
>> To: programm...@jsoftware.com <javascript:;>
>> Cc:
>> Sent: Saturday, July 19, 2014 6:16:58 PM
>> Subject: Re: [Jprogramming] High Speed Train Challenge
>>
>> Hi Pascal,
>>
>> Not arguing against the idea but they are only functionally the same for
>> monadic.
>>
>>    4 *: 4
>> |domain error
>> |   4    *:4
>>    4 +: 4
>> |domain error
>> |   4    +:4
>>    5 *: 4
>> |domain error
>> |   5    *:4
>>    5 *~ 4
>> 20
>>    5 +: 4
>> |domain error
>> |   5    +:4
>>    5 +~ 4
>> 9
>>
>> Cheers, bob
>>
>>
>> On Jul 19, 2014, at 2:59 PM, 'Pascal Jasmin' via Programming <
>> programm...@jsoftware.com <javascript:;>> wrote:
>>
>> > kindof the same as your idea
>> >
>> >    *~(^:3) 12
>> > 429981696
>> >
>> > completely off topic, but would it be a good or bad thing if, assuming
>> there was a shortage of ascii mnemonics, and some need, if monadic +: and
>> *: were redefined considering that +~ and *~ do the same?
>> >
>> >
>> > ----- Original Message -----
>> > From: Erling Hellenäs <erl...@erlinghellenas.se <javascript:;>>
>> > To: programm...@jsoftware.com <javascript:;>
>> > Cc:
>> > Sent: Saturday, July 19, 2014 3:05:03 PM
>> > Subject: Re: [Jprogramming] High Speed Train Challenge
>> >
>> > Another way to do the same thing, but not a solution, is this
> expression:
>> >
>> >     3 (*(*(***)*)*) 4 NB. Funny way
>> > 429981696
>> >
>> > Anyone can find a nice recursive way to write it? My best shot:
>> >
>> >     12 1:`([ * [  $: [: <: ])@.([: * ]) 8 NB. Complicated way
>> > 429981696
>> >
>> > It's a recursion? * $: *
>> >
>> > /Erling
>> >
>> >
>> >
>> >
>> > On 2014-07-19 20:48, Raul Miller wrote:
>> >> Probably, yes.
>> >>
>> >> And I was sort of provocative by not going with the implied
> limitations.
>> >>
>> >> But there's can be quite a bit of ambiguity when key issues are
>> >> implied, rather than addressed or illustrated.
>> >>
>> >> This is a problem I face myself, quite often: How can I be aware of
>> >> important issues which matter to other people, when I am incredibly
>> >> focused on my own point of view?
>> >>
>> >> That said:
>> >>
>> >> (1) Erling Hellenäs had already posted some solutions which satisfied
>> >> the "one verb" constraint using * as that verb (at the time I made my
>> >> 42981696"_ post).
>> >>
>> >> (2) Realizing that derived verbs are J verbs is an important lesson
>> >> which beginning J programmers often overlook.
>> >>
>> >> You can't really be a good J progammer if you don't understand the
>> >> grammar of the language. And it's not that the grammar is hard to
>> >> understand - it's extremely simple. But it's so simple that it's also
>> >> easy to sometimes get by with false generalizations about its rules.
>> >>
>> >> This leads into the almost inevitable "no that's not what I meant"
>> >> sorts of social issues.
>> >>
>> >> So yes, my post was - in a sense - somewhat bratty. But I felt that
>> >> the underlying issue was important enough to raise the point and stick
>> >> with it at least until someone called me on it.
>> >>
>> >> Thanks,
>> >>
>> >
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