I see plenty of correspondents have had a go already.
However, a few examples of use might be helpful. I have just found
t. & T. in NuVoc, having assumed they wouldn't be there yet, so thanks for
that.
Trying t =: t.'' as suggested elsewhere, and T =: T.&'', in a
session with
T each 1 2 3 4 NB. ie 3 threads
+-+-----+-++
|3|3 1 2|0||
+-+-----+-++
I find
timer'Sa 1000' NB. returns correct result for y=1000
+--------+--------+
|0.266998|37048340|
+--------+--------+
timer'Sa t 1000' NB. no time detected
++--------+
||37048340|
++--------+
ts'Sa 1000'
0.273682 481344
ts'Sa t 1000'
1.86e_5 1408
But trying to capture the result of Sa hangs:
ts'q =: Sa t 1000'
.... hourglass ...
in Windows 11. Using the J break batch file doesn't appear to work.
I've now tried timex =: 6!:2 rather than ts =: 6!:2 , 7!:2@]
with a bit more success, which suggests the space query is causing the hang:
timex'q=: Sa 16000' NB. longer time so I can try stopwatching as below
27.1941
erase'q'
1
timex'q=: Sa t 16000' NB. supersonic!?!?
2.41e_5
q NB. no! - this took about 25 seconds to return a boxed
value, from a pyx, I suppose:
+-----------+
|38245553964|
+-----------+
So the session hangs for around 25 seconds while the value for q is found.
(Sa is my best effort so far, and far too slow so far, for Project
Euler Problem 791,
https://projecteuler.net/problem=791 , in case of interest.)
FWIW,
JVERSION
Engine: j904/j64avx2/windows
Beta-a: commercial/2022-04-09T17:57:22
Library: 9.04.01
Qt IDE: 2.0.3/6.2.4(6.2.4)
Platform: Win 64
Installer: J904 install
InstallPath: c:/d/j904-beta
Contact: www.jsoftware.com
Thanks,
Mike
On 09/04/2022 20:04, Henry Rich wrote:
The big news in J904 is multithreading. J verbs can now be run in
different cores, sharing the J global namespaces.
[A version of J with limited support for multithreading was revealed
last year by John Ference of Monument AI. John's work was an
important proof of concept, but the J904 version is an independent
development using pthreads instead of OpenMP. John has agreed with
Jsoftware to give Jsoftware access to the code and testcases used in
his work. We have not used the code.]
Two primitives support multithreading:
(0 T. '') creates a thread on a new core. A thread running a verb
is called a /task/. Even if you don't plan to create tasks, you should
create threads to allow JE to use them for its own purposes.
([x] u t. '' y) executes ([x] <@:u y) as a task to produce a boxed
result. The thread that executed t. continues to run. But the result
is a special kind of box called a /pyx/.
['pyx' is Greek for box, and has been brought into English on occasion
when a word has been needed for a special box. The most recent such
borrowing until now is for the box used by the Royal Mint to hold
coins for assay.]
A pyx looks on the outside like any other box. You can pass it as an
argument. But as soon as you look inside it, your thread is blocked
until the task producing the pyx's value has completed. Then you see
the value, and your thread continues.
Tasks share the global namespaces and thus can freely read, write,
stomp on, and delete names visible to other tasks.
We encourage you to experiment with threads and tasks. We are sure
that a layer of synchronizing primitives - semaphores, locks, and
mutexes - will be needed, but we would like to get practical
experience with tasks before we implement them. Suggestions welcome.
Henry Rich
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