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 <[email protected]> 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 <[email protected]> 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 <[email protected]> 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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