[Jprogramming] Show cause hearing: maximum rank will be 63

[Henry Rich]

Sounds like a limit of 63 would still give you something to live for, 
then. :)

Henry Rich

On 4/6/2021 10:43 AM, Devon McCormick wrote:
> The point of my story about the rank-64 bug in IBM's APL of the 70s was
> that hacking the system was the only use I ever encountered for
> high-dimensional arrays.  I have never used anything higher than rank 6 in
> actual code but that's over the past 50 years, so there's still time.
>
> On Tue, Apr 6, 2021 at 10:30 AM Henry Rich <henryhrich at gmail.com> wrote:
>
>> Space saving.  The V struct, describing a verb, fills 128 bytes, and I
>> need to add to it.  If the maximum rank is reduced from 65535 to less
>> than 256, I can avoid requiring a third cacheline.
>>
>> Henry Rich
>>
>> On 4/6/2021 12:20 AM, Roger Hui wrote:
>>> I repeat my question, what are the benefits of restricting array rank to
>> be
>>> ≤ 63 ?
>>>
>>>
>>>
>>> On Mon, Apr 5, 2021 at 8:28 PM Henry Rich <henryhrich at gmail.com> wrote:
>>>
>>>> 'May be'.  Have you actually implemented it?
>>>>
>>>> I find it very hard to believe that a J sparse array would be the best
>>>> choice for any database.  It seems to me to:
>>>>
>>>> * take lots of memory per value
>>>> * have limited or inefficient queries
>>>> * be very slow for updates, as the entire table must be copied
>>>>
>>>> Please prove me wrong.
>>>>
>>>> Henry Rich
>>>>
>>>> On 4/5/2021 10:04 PM, Igor Zhuravlov wrote:
>>>>> On Sun, Apr 4, 2021, 11:52 PM Henry Rich <henryhrich at gmail.com> wrote:
>>>>>> I propose that the maximum value for a rank, whether of a verb or a
>>>>>> noun, will be 63.  Minimum verb rank will be _63.
>>>>>>
>>>>>> You got a problem with that?
>>>>> A database in J may be implemented as a sparse boolean orthotope where
>>>> each
>>>>> axis corresponds to some attribute (field, column of relational table),
>>>> and
>>>>> value 1 ("true") marks tuple [1].
>>>>>
>>>>> A restriction proposed will limit a number of attributes to <64 for
>> this
>>>>> application. It would be sad but not fatal. I'd prefer to have this
>> limit
>>>>> larger, say, O(1e5).
>>>>>
>>>>> References:
>>>>> [1]
>> http://www.jsoftware.com/pipermail/general/2000-February/003102.html
>>>>>        Jforum: Sparse Array as Database ?
>>>>>        Roger Hui
>>>>>        Thu Feb 10 19:06:50 HKT 2000
>>>>>
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>


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