[Jprogramming] The n-cell model of an array

[Jose Mario Quintana]

> For this to happen J functions have to be defined for handling arrays of
nothing?

I have not followed this thread, or any other recent thread, closely but
this might shed some light:

"
Zero Frame. If the frame contains 0 (as in 3 *"1 i. 0 4), there are no
argument cells to apply v to, and the shape of a result cell (the value of
 sir) is indeterminate. Pesch [1986] describes a variety of strategies to
address this problem. In J, the shape is calculated if v is uniform (see
below); otherwise v is applied to a cell of fills.
"

Rank and Uniformity  Roger K.W. Hui

http://www.jsoftware.com/papers/rank.htm

I hope it helps


On Wed, Dec 20, 2017 at 4:03 AM, Erling Hellenäs <erling at erlinghellenas.se>
wrote:

> Hi all !
>
> Could we avoid doing these peculiar things in the rank operator if we
> enabled the handling of arrays of nothing?
>
> The verb injected in Rank would then have to give a valid result for an
> array of nothing?
>
> For this to happen J functions have to be defined for handling arrays of
> nothing?
>
> Would it be possible to define an algebra for the handling of arrays of
> nothing?
>
> Could this be the same as enabling missing data?
>
> Cheers,
>
> Erling
>
>
>
> Den 2017-12-20 kl. 09:46, skrev Erling Hellenäs:
>
>> This is a mathematical concept: https://en.wikipedia.org/wiki/
>> Empty_product /Erling
>>
>>
>> Den 2017-12-20 kl. 09:39, skrev Erling Hellenäs:
>>
>>> */i.0
>>>
>>> 1
>>>
>>> Here the interpreter automatically adds a 1 to get this peculiar result.
>>>
>>> /Erling
>>>
>>> Den 2017-12-19 kl. 20:01, skrev Raul Miller:
>>>
>>>> An empty tank zero array would be inconsistent.
>>>>
>>>> The number of elements in an array is the product of its dimensions, and
>>>> the multiplicative identity is 1, not 0.
>>>>
>>>> Thanks,
>>>>
>>>>
>>> ----------------------------------------------------------------------
>>> 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
>