[Jprogramming] Two implementation questions

[Elijah Stone]

Thank you Eric, that makes a lot of sense.

On Mon, 2 Aug 2021, Eric Iverson wrote:

> bit data type:
> It is partly an issue of resources and how to spend them. Adding a bit data
> type is a large amount of work. And at least so far we have found better
> areas to work on. Also the playing field for those old arguments have
> changed and continue to change. APL already has them and it should keep
> them. J doesn't have them and so far doesn't miss them except for some
> academic arguments. In the early APL days memory space was critical and
> they also allowed some fast algos. Memory is much less important now and
> new hardware allows many fancy tricks.
>
> For J, we have decided they are not worth the effort of complexity it would
> add to the JE.
>
> On Mon, Aug 2, 2021 at 4:01 PM Elijah Stone <elronnd at elronnd.net> wrote:
>
>> Apologies if this is the wrong place for this.
>>
>> First: what's the deal with bitarrays?  I have heard APL implementors
>> state with great conviction that they are worthwhile and have led to great
>> performance increases; and I have heard J implementors state with equal
>> conviction that they are not worth their while at all.  I don't know whom
>> to believe!
>>
>> Second: is it worth it to add padding for >1-rank arrays?  It seems
>> convenient for major cells (and perhaps more minor cells as well) to be
>> aligned, and I know of at least one high-performance in-place high-rank
>> transposition algorithm which requires some degree of padding/alignment.
>> J's array structure doesn't seem to make any allowance for more than one
>> shape.  Has this approach been tried and found lacking, or is it just
>> untrodden ground?
>>
>>   -E
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