That's a good point -- the symbolic expression of "just the unique
items" from the original post is a different concept from the "unique
results".
And, if N has repeated elements (as opposed to elements which when
combined produce the same results), this can raise further
questions... which gets back to: what is this being used for?
Thanks,
--
Raul
On Mon, Jun 25, 2012 at 12:57 PM, R.E. Boss <r.e.b...@planet.nl> wrote:
>
> ;<@(*{.)\.>:i.5
> 1 2 3 4 5 4 6 8 10 9 12 15 16 20 25
>
>
> ~.,*/~>:i.5
> 1 2 3 4 5 6 8 10 9 12 15 16 20 25
>
>
> R.E. Boss
>
>
>> -----Oorspronkelijk bericht-----
>> Van: programming-boun...@jsoftware.com
>> [mailto:programming-boun...@jsoftware.com] Namens Raul Miller
>> Verzonden: maandag 25 juni 2012 18:51
>> Aan: Programming forum
>> Onderwerp: Re: [Jprogramming] Multiplying with folds
>>
>> Why do you want this?
>>
>> If it's efficiency, note that the size of the dense array */~N is
>> typically less than the size of a linked list which only represents
>> the products of unique combinations of pairs (if we assume that linked
>> list pointer size is approximately the same size as a number), and
>> also note that typical cpu cache implementation heavily favors regular
>> operations.
>>
>> If it's because you need unique values, you might consider using:
>>
>> ~.,*/N
>>
>> If it's for some other purpose, the topic might have inherent interest...
>>
>> Thanks,
>>
>> --
>> Raul
>>
>> On Mon, Jun 25, 2012 at 12:37 PM, David Vaughan <purpleblue...@gmail.com>
>> wrote:
>> > I'm looking for a verb to achieve the same thing as just the unique items
>> > of */~ N, i.e. n0*(n0 ... nk) n1*(n1 ... nk) n2*(n2 ... nk) ... nk*nk.
>> >
>> > I can easily create the result, but I want to be able to calculate it more
>> > efficiently, without having to do the multiplications that will ultimately
>> > be redundant (which would be ~.,*/~ N).
>> >
>> > I'm not particularly good with folds and similar concepts, so I expect the
>> > solution is relatively simple. Can anyone help?
>> >
>> > Many thanks.
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