Here is another approach using __&q: to generate only unique factors due to
their unique prime factorisations:
factors=: (*/ . ^ [: |:@:>@,@{ <@i.@>:)/@(__&q:)
Cheers,
Louis
> On 3 Oct 2017, at 12:23, Erling Hellenäs <[email protected]> wrote:
>
> Hi all!
>
> a=: 2 5 7
> f=: 1 :'/:~ (#: }. i.2^#y) u@# y'
> +/f a
> 2 5 7 7 9 12 14
> */f a
> 2 5 7 10 14 35 70
> <f a
> ┌─┬───┬─────┬───┬─┬───┬─┐
> │2│2 5│2 5 7│2 7│5│5 7│7│
> └─┴───┴─────┴───┴─┴───┴─┘
>
> With the no element combination deliberately dropped.
>
> Cheers,
> Erling
>
>
>
>> On 2017-10-03 00:45, Erling Hellenäs wrote:
>> Hi all !
>>
>> a=: 2 5 7
>> f=: 1 : '/:~(#: }. i. 2 ^ # y) ([: u/ #) /"1 y'
>> + f a
>> 2 5 7 7 9 12 14
>> * f a
>> 2 5 7 10 14 35 70
>>
>> Cheers,
>> Erling
>>
>>> On 2017-10-02 19:45, Erling Hellenäs wrote:
>>> Hi all!
>>>
>>> You don't want the combination of zero elements?
>>>
>>> a=: 2 5 7
>>> /:~(#: i. 2 ^ # a) ([:+/#) /"1 1 a
>>> 0 2 5 7 7 9 12 14
>>> /:~(#: i. 2 ^ # a) ([:*/#) /"1 1 a
>>> 1 2 5 7 10 14 35 70
>>>
>>> Guess I could drop it.
>>>
>>> Cheers,
>>>
>>> Erling
>>>
>>>> On 2017-10-02 18:49, Skip Cave wrote:
>>>> Given a set of integers, what is the most concise and or efficient way to
>>>> list the numbers along with the sum of all combinations of the numbers? the
>>>> products of all combinations?
>>>>
>>>> for example:
>>>>
>>>> a =. 2 5 7
>>>> + f a NB. 2, 5, 7, (2+5), (2+7), (5+7), (2+5+7)
>>>> 2 5 7 7 9 12 14
>>>>
>>>> * f a NB. 2, 5, 7, (2*5), (2*7), (5*7), (2*5*7)
>>>> 2 5 7 10 14 35 70
>>>>
>>>> The function 'f' should work for any verb and any size right argument noun
>>>> vector.
>>>>
>>>> Skip
>>>>
>>>> Skip Cave
>>>> Cave Consulting LLC
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>>>
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