Multiplication of an integer array I get an error:
AAA =: af_create_array_jaf_ i. 4 4
get_jaf_ AAA
0 1 2 3
4 5 6 7
8 9 10 11
12 13 14 15
=: af_matmul_jaf_ AAA,AAA
|af cd call error result: assert
| 'af cd call error result' assert 0[LASTERROR=:(":0{::r),' ',(x{.~x i.' '),'
',af_err_to_string
Standard Library is also an item of the Help menu in JQT.
~ Gilles
Le 2022-02-02 à 18:03, chris burke a écrit :
I didn't even know there was a standard library
The standard library docs are linked from System on the wiki left menu:
https://code.jsoftware.com/wiki/Standard_Library/Overview
O
> I didn't even know there was a standard library
The standard library docs are linked from System on the wiki left menu:
https://code.jsoftware.com/wiki/Standard_Library/Overview
On Thu, Feb 3, 2022 at 3:32 AM 'Viktor Grigorov' via Programming <
programm...@jsoftware.com> wrote:
> Thank you fo
For what it's worth, here's an hmac with a more production-oriented design:
hmac=: {{ NB. https://en.wikipedia.org/wiki/HMAC
NB. u: hash function (on literal sequence)
NB. n: block size for hash
if. 0=#(u'')-.,hfd i.16 do.
v=. a. {~ _2 dfh\ u
else.
v=. u
end.{{
NB.m: key
Set a flag on x. Check it at the same time you check whether the usecount
is 1 to perform an in-place operation. If the operation is one of a few
interesting ones (catenate, amend), look up the corresponding hash table
and update it too. Otherwise discard the hash table.
(As for where to pu
Hmm...
https://wiki.jsoftware.com/wiki/Guides/UnicodeGettingStarted mentions
hfd and dfh.
At one point, dfh and hfd were part of the 'convert' addon. This has
since been incorporated into the base library (and require'convert'
succeeds, for backwards compatibility purposes, but does nothing).
We
Thank you for that, I see the issues in my attempt.
Two comments perhaps more pertinent to the people attempting to revitalize the
wiki: how is one to know:
- that arbitrary(?) base numberal to decimal exist, matching the regex
'\d+b_?\w+'?
- how is one to know of the existence of hdf/dfh?---I d
the important detail is that m&i. uses a static snapshot of m at the time that
& is executed/bound.
A workaround is to optimize SET, ADD, UPDATE, DEL for bulk operations (multiple
items processed at once (] F..) super useful), and after bulk operations,
"redefine" (just repeat execution of sa
Here's an implementation of the hmac algorithm which supports using an
somewhat arbitrary hash function (I have assumed that the hash
produces a literal result, as opposed to a bit stream, a large
arbitrary precision integer or a sequence of integers representing
bytes), but other than that optimiz
The algorithm works with raw binary -- it will not be the case that
all bytes will have ascii graphics.
And, that relates to the other problem with your implementation: you
are using a hexadecimal representation of a binary result as if it
were equivalent to that binary result.
I hope this makes
On Wed, Feb 2, 2022 at 7:37 AM Scott Locklin wrote:
> I wrote this a couple of years ago. It's a bit more bit fiddly, and I know
> it works as it was used in production to talk to an exchange.
>
> NB. hmac signature
> NB. x key, y needs signature
> NB. key may need to be made raw first
> hmac=: 4
I tried padding with 0 0 1 1 0 0 0 0 ('0') and with 0 0 0 0 0 0 0, and with
your padkey function, but I don't get the proper results. Also, the 0x5c and
0x36 from the ascii table correspond to '/' and '6', yours results in
ungraphable members.
You said other issues exist as well, I would appreci
I wrote this a couple of years ago. It's a bit more bit fiddly, and I know
it works as it was used in production to talk to an exchange.
NB. hmac signature
NB. x key, y needs signature
NB. key may need to be made raw first
hmac=: 4 : 0
key=. x,(128 - #x) # 0{a.
ixorkey =. ((22 b.)&(16b36) a. i.
Actually, for the general case, the hash function may have an output
size smaller than the block size.
So:
padkey=: {{
if.x < # y do. y=. u y end.
x{.y,x#{.a.
}}
FYI,
--
Raul
On Wed, Feb 2, 2022 at 6:51 AM Raul Miller wrote:
>
> On Wed, Feb 2, 2022 at 4:41 AM 'Viktor Grigorov' via Progra
On Wed, Feb 2, 2022 at 4:41 AM 'Viktor Grigorov' via Programming
wrote:
> I wanted to see if J could be faster than bespoke C programs (specifically
> aircrack-ng, ~10k/s on my machine).
> From the wiki pages for SHA1 (turns outs there exists a foreign so I dropped
> it), HMAC, and PBKDF2I assem
That's a possibility, but how would you know when x changes, or is
assigned to a different name?
Henry Rich
On 2/1/2022 8:27 PM, Elijah Stone wrote:
On Mon, 31 Jan 2022, Henry Rich wrote:
The deficiency in J is that m&i. gives you a hashtable for searching
m, but if you modify m you have to
My solution there was also quite verbose.
Golfing an implementation might be a worthwhile exercise.
Thanks,
--
Raul
On Wed, Feb 2, 2022 at 6:15 AM 'Michael Day' via Programming
wrote:
>
> More chat on this old thread.
>
> Finished at last! 50 stars for something or other...
> It took quite a
More chat on this old thread.
Finished at last! 50 stars for something or other...
It took quite a lot of tweaking to build in the restrictions to the
"amphipods' " movements that I'd
mentioned in my msg of 23Jan, below. I'd overlooked the paragraph
(originally without J's NB. as
Raul pointed
Xash:
(3 ({. ~: {:)\ 0,],0:)
That's brilliant! It only took me 5 minutes to understand what this means
this time :-)
Elijah:
Thank you for the clarification. The adverb rule is foreign to me, I will
have to explore some examples to see why it makes sense for it to be
different from the verb rule.
I’ve successfully tested it on linux at least, looking through the source
though it looks like it only reads from parquet at the moment, I must not
have tested writing yet.
The bindings aren’t too complex though, it might be straightforward to add
a writeParquet verb if that functionality is still
Hello,
I wanted to see if J could be faster than bespoke C programs (specifically
aircrack-ng, ~10k/s on my machine).
From the wiki pages for SHA1 (turns outs there exists a foreign so I dropped
it), HMAC, and PBKDF2I assembled:
sha1=:1&(128!:6)
bs=:512%8 NB. block size in bytes for md5, sha1, sh
Thanks Aaron - that looks really promising. Will check it out & see if I
can get it to work.
On Wed, Feb 2, 2022 at 8:48 PM Aaron Ash wrote:
> There's also these J bindings that can be used to read/write parquet
> files directly from J: https://github.com/interregna/JArrow
>
> On Wed, Feb 2, 202
> Now why steps 10-13 result in the next row of a sierpinski triangle, I
> don't know, I guess it has to do with generating a Pascal triangle.
It's not that important for learning J, but it gives a hint why the
seemingly confusing `72#:~8#2` was used. `bm{~3#.\row` maps three consecutive
bits to b
Thanks Stefan,
Had a quick look and liked the sound of being able to work with
larger-than-memory datasets by analysing streams from data sources, however
wasn't so impressed by the DuckDB showing (out-of-memory) on this benchmark
site https://h2oai.github.io/db-benchmark/ However it looks like the
On Wed, 2 Feb 2022, Igor Zhuravlov wrote:
1.2. Dictionary consists of keys and values.
1.2.1. A pair (key,value) is a mapping establishing structure.
1.2.2. A mapping from key to value is denoted as: {key -> value}.
Ordinary j arrays permit many keys. Rather than key -> value, they ha
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