The APL Orchard

12:08 AM

@Adám Not really. I'm aware of that overflow possibility; perhaps I'll end up with -4 just to be sure. (10GB file processed sequentially takes 25min on my PC; I don't think there are many larger ones)

@MartinJaniczek Speaking of sequentially, I'm toying with the isolates.llEach. I need to give it all values explicitly, right? It has its own "scope"

Adám

@MartinJaniczek Correct, because each is its own APL interpreter.

@MartinJaniczek Ah, you're using this to time performance. I'm not sure if you have a particular reason you want the time as (mins,secs,ms). You probably don't even need that kind of resolution. Maybe keeping the start and end as UNIX time (20⎕DT'J') would be more suitable, then you don't need a conversion as they are already counts of seconds. You can then do 0 60⊤endt-startt to get the (mins,secs) as a result, even if the minutes exceed 60.

If you do need ms resolution, use 12 instead of 20 and use 0 60 1000⊤ to get (mins,secs,ms).

Martin Janiczek

12:24 AM

@Adám Correct, I want to log elapsed time for a function. Thanks for the tips

No particular reason for the format, this was just the first working way I stumbled upon

Adám

Ah, so you're just using this for yourself, not as part of the actual code?

Martin Janiczek

No, I wanted to keep it in the actual code

Adám

OK.

Martin Janiczek

I'm aware of cmpx etc. but these didn't seem right for logging in a long-running task

Adám

No, you're absolutely right about that.

Also, how did you manage to pick up so much knowledge of both core APL and the utilities, in such a short time‽ I'm in awe.

Martin Janiczek

12:30 AM

Thanks :) A few weeks worth of sank evenings and nights I guess. It's real fun so far!

> ISOLATE ERROR: All processes are in use

Ow.

I think I remember a pool of sorts being advertised in some doc, but can't recall it.

Any ideas? I guess my rightside argument to the llEach has overflown some threshold

(On ~400 items it was fine)

Adám

How many elements does the right argument have?

Martin Janiczek

47k

Adám

There's no need to start significantly more threads than you have processors.

Martin Janiczek

I suppose 47 thousand is significantly more :)

Adám

Depends on your computer, of course ;-)

Each thread has an overhead, so you want to split your data into an appropriate number of chunks for the current machine. Maybe 1111⌶⍬ chunks is fitting.

Martin Janiczek

12:38 AM

I wonder if the pool and "reuse threads" approach wouldn't be easier for me

Adám

Possibly. Then you need to use the "new isolate" function.

@MartinJaniczek But if Process¨data works (albeit in serial), then chunking your data and running ⊃,/Process¨IÏ chunkedData should work.

Martin Janiczek

Hm, that isn't as complex as I imagined

Adám

And you know how to cut into N approximately equal sized chunks?

Martin Janiczek

Sorry I had to go do something about my hypoglycemia. Hmm I think I saw something with the partition function but I don't recall the specifics.

if I have 98 items let's say, and i want to do 4 chunks, then ... ceil(98/4) = 25 as expected, and I need to get (1 ..0 repeated 24 times..)..repeated 4 times.., which I guess rho can help me with

Is that overcomplicated?

Adám

12:54 AM

No, exactly, you're on it.

@MartinJaniczek Instead of "repeated 4 times" you can just reshape to the argument length.

a⍴b↑1 is a fairly common pattern in APL.

Martin Janiczek

yes that was in my head but I didn't write it that way. I wanted to get the first "copy" of 1,0,0,0... done and then rho it to the needed length.

alright I'm gonna try that in my workspace. Sounds like a plan :)

funny thing, just a thought. I was reading one of the lessons from this room last night, about the Stencil operator. You mentioned it can be used to get groups with a configurable step. So it maybe could also be used to split a vector into n chunks?

Adám

Yeah, it could, but it isn't designed for it, so it tries to centre the first group on the first element, padding with prototypical elements on the left. This takes some effort to work around.

Martin Janiczek

Right.

(98⍴1,24⍴0)⊂⍳98 does the trick

Adám

Another approach is reshaping into a matrix with N rows, and then splitting that. But this has issues if the division isn't exact.

@MartinJaniczek Sure, although 1,24⍴0 can be written simpler: 25↑1

Martin Janiczek

Man, the default behaviours of "edge cases" have really been thought through, haven't they. Like repeating the source data if reshaping "above" its length. Fits so nicely :)

Hm, 25↑1, so that uses the fact that ↑ fills "above length" with 0? Nice

Adám

1:03 AM

That's right. Note that 25↑'a' fills with spaces, and 25↑⊂4 2 fills with ⊂0 0s.

Martin Janiczek

right, "default element", as it were?

Adám

@MartinJaniczek Prototype.

dzaima

@Adám wat

Adám

@dzaima Update your interpreter.

dzaima

ah k

Adám

1:11 AM

no, apl.

:D

:D

;-)

What's happening there btw?

Adám

A bug.

18.0 had some pretty severe bugs when it was first released, and we had to eventually recommend not using it for production systems. We recently re-released it and removed that recommendation.

Bubbler

1:15 AM

I can't imagine how that code could break so badly

Martin Janiczek

Is (leftargs∘Process)¨ equivalent to leftargs∘Process¨? My guess is no - each would bind earlier than jot?

dzaima

@MartinJaniczek they are equivalent

Adám

@MartinJaniczek Yes, they are the same. All operators bind from the left (they have long left scope).

@MartinJaniczek Do you have ]boxing on?

dzaima

@dzaima and now to redelete aplkeys.sh..

Adám

Actually, this should work with the bot: ⋄ ({a}∘{b})¨ ⋄ {a}∘{b}¨ ⋄ {a}∘({b}¨)

Martin Janiczek

1:18 AM

@Adám I do but admittedly I didn't try to show how it parsed. Re above, looks like my head model of how operators parse still needs fixing :)

Dyalog APL

@Adám
    ¨
  ┌─┘
  ∘
┌─┴─┐
{a} {b}
    ¨
  ┌─┘
  ∘
┌─┴─┐
{a} {b}
  ∘
┌─┴─┐
{a} ¨
  ┌─┘
  {b}

dzaima

@MartinJaniczek you just go left-to-right, and at every point you can bind anything, you do.

alternatively, to parse an operator expression, insert a closing parenthesis after every monadic operator and after every dyadicOperator arrayOrFunction, and prepend to the expression as many opening parentheses needed

Adám

@dzaima While technically correct, that method is error-prone because of intent bias: 1∘+⍣3 4 → 1∘+)⍣3)4 → ((1∘+)⍣3)4

dzaima

@Adám right, that's just a single step of a multi-step parsing process - 1) parenthesize strands; 2) separate out operator expressions; 3) parse operator expressions; 4) parse either as a train or regular expression

Adám

"regular expression" ⍨

dzaima

1:26 AM

@Adám i did think about it, but didn't think it was worth editing

Adám

Took me an extra couple of seconds to understand.

Regular expressions don't even have an official or formal name in APL circles, though I call them "explicit".

Bubbler

I could say "function expression" or "array expression"

Adám

1:41 AM

That's nice too, and lends itself well to add "operator expression".

Marshall

@dzaima Preliminary spec for identity values here. I decided to restrict it to right identities since I can't figure out how to justify left ones. That cuts out √|<≤, which seems to me to be a good thing. I also allow an identity that only works on the range of the function, which makes ≠ and = work. Largest invariant set (a subset of the range) might be more precise but I can't think of a situation where it would matter.

Martin Janiczek

Any idea how I can debug this?

Adám

Also, {⍺+⍵} is a function expression, but it feels wrong to call it tacit.

Martin Janiczek

weightings_and_answers←⊃,/leftargs∘get_weighting_and_answer¨ IÏ chunked_data
VALUE ERROR

(pointing at the get)

Adám

Ah, debugging multi-threaded code is not fun.

Martin Janiczek

1:43 AM

Do you think it's an error inside the function?

Adám

It could be. Does it work with ¨ instead of IÏ?

Marshall

@Marshall I'd like ˝ to reflect the array's cell shape when the operand maps over array arguments (e.g. arithmetic or Each), except that that property isn't actually well defined. Might just hack it into the spec anyway.

Martin Janiczek

Seems so (I have a ⎕←inside and it's happily printing)

Adám

@MartinJaniczek That would be problematic, as it'd try to print in a different interpreter.

Martin Janiczek

I'll try to remove it then.

Adám

1:45 AM

But still, that shouldn't give a value error.

Is the function relying on a global?

Martin Janiczek

I went over what globals it reads and gave them to it as left args. Maybe I missed some

Adám

@MartinJaniczek What kind of function is get_weighting_and_answer? Dfn, tradfn?

dzaima

@Marshall it could be as "well defined" as empty reduction - just say that functions have a scalar-ness property, which ˝ can take advantage of

Martin Janiczek

It's multi-line dfn

Adám

Maybe insert 0::⊂⎕DM or something at the top to get a Diagnostic Message into the result instead of erroring. Then you can have a look at that.

If you want to be really fancy, you could use ⊂⎕JSON⎕DMX to get more detail.

Marshall

1:49 AM

@dzaima How does that work for something like -⌾⌽? I need a little more detail to understand what you mean.

Martin Janiczek

@Adám For some reason that did nothing (when run with llEach). I still get that VALUE ERROR and nothing gets assigned.

I'm reading the doc for isolates, perhaps isolate.Config 'onerror' 'debug' etc. can help me

dzaima

@Marshall either -⌾⌽ inherits the scalar-ness property of -, or it doesn't, it's your decision. (i'm not really saying anything novel, just mentioning a way for it to not be "not well defined")

Adám

@MartinJaniczek Aha, but I think that tells us that the error isn't happening inside the function. I'm suspecting that IÏ somehow fails to send its tacit operand along properly. Wild shot: Try (⊂⊂leftargs)get_weighting_and_answer¨IÏ

@MartinJaniczek You can definitely try it. If you get stuck, then I'll ask Morten (who is our isolate guy) to help you.

Razetime

morning

Adám

@Razetime Unfortunately.

I've become a night owl ∘.○

Martin Janiczek

1:57 AM

@Adám Didn't help. I'll actually cut my losses for today (it will be 3AM) and start with a fresh mind tomorrow. Bless Git for snapshotting working states :) Thanks for all the help Adam! And good night/morning/whatever everybody :)

Marshall

@dzaima The identity element is defined entirely in terms of the input-output mapping while it sounds like scalar-ness would use the representation, so that would be worse. I could say that a function is each-y if it's identical to F¨ for some F, but the issue with that is that you might be able to find the identity of a function and not be able to use it for ˝ because you don't know whether the function is each-y or not.

Razetime

@Adám oh nooo

Marshall

But maybe that possibility doesn't actually come up?

Adám

@MartinJaniczek I'll ask Morten to contact you tomorrow. Any particular time is best?

Martin Janiczek

@Adám I can come here 8 hours from now but I'll probably lurk here all day.

dzaima

2:00 AM

@Marshall I guess I'm thinking in terms of dzaima/BQN, where identity is just another way to query a value (at one point I had to temporarily extend F⎊G to inherit the identity of F, and for that a simple mapping wouldn't do)

Martin Janiczek

@MartinJaniczek I think it's most sensible for me to recheck whether it still works with the 400 elements and llEach before chunking (I suppose I messed something up), and then with 400 elements after chunking, and only then with the full data + chunking.

@MartinJaniczek Anyways, logging off.

Adám

○/

dzaima

@dzaima (heh, {𝕊´⟨⟩: 0 ; 0+𝕩 ; 𝕨+𝕩})

Razetime

2:28 AM

@Adám It looks like inlining ngn's code to run after the page loads did the trick: aplchat.js

Adám

!

Razetime

2:44 AM

however, still need to find a way to make the latest version work.(somehow npm does it)

Adám

While a fun project, I'm still not exactly sure what the purpose is. Since others can't see the result, it doesn't really work for demonstration purposes.

Razetime

yeah everyone needs to have it installed for it to be useful

was still fun trying to make it

Adám

Unless you make it put the result into the input field, and click "send"…

Razetime

so, add evaluation to text field..

Adám

Actually, maybe most useful would be to allow input of APL in the text field, display an extra "eval" button next the the normal ones, which when pressed adds the result below the expression, ready for you to hit Enter if everything is as desired. If not, you can edit and hit eval again…

Hitting eval would also make sure there's 4+6 spaces to the left of the expression, and 4 spaces before each line of the result.

Razetime

2:54 AM

that sounds very doable

Bubbler

@Adám I was thinking exactly this, to make it display like in the interpreter

Adám

Basically a mini-TryAPL.

In fact, it wouldn't even need to use ngn/apl. It could ship off the evaluation to TryAPL proper.

I would definitely use this for teaching purposes, to avoid making mistakes and have the bot respond to those.

Razetime

@Adám tryapl has a js api?

Adám

Yes, now it does.

Razetime

cool, where do I read up on that

Russtopia

3:00 AM

Hi, does anyone know if there is documentation for GNU APL's ∇-editor? It seems to support some commands but not all, as opposed to Dyalog. GNU APL's main docs gnu.org/software/apl/apl.html#Section-3_002e13 just state some vague things such as "...the ∇-editor commands for recalling function lines (and which are not fully supported in GNU APL)."

[See Dyalog docs help.dyalog.com/18.0/index.htm#Language/Defined Functions and Operators/TradFns/APL Line Editor.htm]

Adám

@Russtopia Not a whole lot of GNU APLers hang out here, though @EliasMårtenson might know. However, they do seem to monitor Stack Overflow, so you could ask there.

Russtopia

OK I wasn't sure if I should ask as a regular SO question or here. Thanks.

Adám

@Razetime It isn't publicly documented, but it is very simple: You submit ["",0,"","apl code"] and get back ["stuff",number,"stuff","result"]

@Razetime You should be able to glean it from tryapl.org/lib/tryapl.js beginning at line 281 or so (inside jarvisProcess). You can skip all the session manipulation. You just need to create the request.

It should probably strip away all but the first line of the text field before evaluating, as this would allow you to edit your code and re-evaluate, without having to remove the stale result.

Razetime

3:24 AM

@Adám so, give an XMLHTTPRequest to tryapl.org with that array

Adám

Yeah, I think that'd work.

CMC: Given a tradfn nested representation (vector of character vectors), return the list of used (outside strings and comments) names (including system variables) that have not been localised by the header or locals lines.

E.g. given ' Foo;local;⎕ML' ' ⎕IO←0 ⋄ ⎕ML←1' ' local←↑⍳global' return '⎕IO' 'global'

Bubbler

3:53 AM

vars~locals, where vars gives all identifiers in the entire code and locals gives only the ones on the first line

Adám

@Bubbler lines, but sure.

Bubbler

An identifier would match... wait, does \w match Unicode letters?

Adám

Only if you ask it to.

Oh, you can take the name of an existing function instead, if that helps.

@Bubbler I don't think you need to specify that so carefully. You can get all used identifiers in an existing function with ⎕REFS. (If you have the code, you can always make it exist temporarily.)

Bubbler

That would be more convenient, as the regex would match control keywords too

Feeds

0

Q: What are the supported editing commands for the GNU APL line editor (∇-editor)?

The GNU APL documentation on the line editor seems to assume one already knows how to use it. I only see mention of what commands/syntax '... are not fully supported in GNU APL'. Compare with the documentation of Dyalog's APL ∇-editor, or MicroAPL. I'd be willing to prepare a patch to submit for ...

Razetime

4:05 AM

@Adám I've tried this: jsfiddle.net/razetime/7h93kx4r/1

Bubbler

@Adám Then I think this works

(example from here)

Adám

@Bubbler Nice, but fails on this.

Razetime

not getting a response yet

Adám

@Razetime Something doesn't match. You have open("GET", "https://tryapl.org", true) where TryAPL has open("POST", "Exec", true)

Razetime

I'm not sure why it has "Exec" as the url

Bubbler

4:13 AM

I think ⎕R and ⎕S are missing on this page?

Razetime

oh ok got it

Adám

@Razetime Because on the APL side it has to call the Exec function.

Razetime

got it lol

Adám

@Bubbler Yeah, technically they are neither functions nor operators, and the last system operator isn't listed either. I suspect that page was/is auto-generated, and until recently when I complained about it, the interpreter didn't know how to self-report its system operators.

Bubbler

Second attempt

Apparently the regex matches ; IN and correctly gives IN but I'm not sure why

Adám

4:20 AM

@Bubbler Huh, it is missing a lot of names.

Bubbler

(and obviously it doesn't handle the case where ;name appears in a string)

Adám

@Bubbler Logged as issue 18743

Bubbler

Last version

Adám

@Bubbler You can fix that. And comments too. Also needs to handle ∆⍙ in names.

I've got a 65-byte solution with a completely different approach. (Doesn't use ⎕REFS.)

@Razetime So, did you get a proper response?

Razetime

yes

Adám

4:30 AM

Cool. Looking forward.

Bubbler

Fully working 76

I don't have time to golf it though

Adám

@Bubbler I think I spot multiple issues. My best so far with your approach is 84.

Bubbler

Then I give up

Adám

Don't sweat it. This is hard. My your-approach solution also fails on some cases.

If anyone else wants to break their teeth on this, here's a stress test:

 Foo;∆localÁ;⎕ML⍝;global
⍝;global
 ;⍙localB
 ';global'
NOTGLOBAL:global'notglobal' ⍝ notglobal
 ∆localÁ ⍙localB
 ⎕ML ⎕IO

Should return 'global' '⎕IO'

Razetime

4:51 AM

Ok, time to test the userscript

⍳5
1 2 3 4 5

great

Adám

@Razetime Just missing insertion of 6 leading spaces before ⍳5

Razetime

there

yup, works on chrome as well

@Adám gist.github.com/razetime/8d0be74e104ac54b1e55d57bec8c2156

Adám

Wow, that's not a lot of code.

Razetime

yeah it's surprisingly short

it adds an ⍎ button to the side

Adám

(Still strange that tampermonkey doesn't detect the userscript)

Razetime

4:59 AM

hmm I just tried it on tampermonkey

Adám

I you sure you don't need // @namespace http://tampermonkey.net/?

Razetime

yeah you can remove that

Adám

I was just thinking that that might prompt TM to notice it.

Razetime

I'm trying it right now and it seems to be working

Adám

@mwchase Hi there. Interested in APL?

Razetime

5:02 AM

@Adám did you add it using Create new script..?

Adám

@Razetime I'm not saying it doesn't work, I'm saying that I distinctly remember TM noticing when I view the raw source of a US.

Razetime

oh alright

Adám

Seems to be working. Amazing.

Razetime

      kewl
VALUE ERROR: Undefined name: kewl
      kewl
      ∧

Adám

@Razetime Two feature requests: add accesskey="x" and focus on the input field after executing.

Razetime

5:07 AM

ok

Adám

I just added field.focus(); at the very end after field.value = and that does the trick.

Razetime

yeah that should work

Adám

Thought: Equip every multi-line input field on every page with a little ⍎ in the top right corner… APL everywhere!

Actually, once I know how to use it and can use the accesskey, I don't need the button. And it'd anyway be hard to style so it doesn't clash with any CSS ever.

Razetime

@Adám there's a way to position a button inside a textarea

Adám

But that's just a thought. For now: This is amazing, Razetime. I'm so going to use this. Once you publish it, we should mention it on the Wiki, both on the Orchards page, and under "Running APL".

Razetime

5:12 AM

@Adám gist.github.com/razetime/8d0be74e104ac54b1e55d57bec8c2156

the funny thing is alt x here clashes with my keyboard layout so it outputs ⊃

Adám

@Razetime Wait, left Alt?

Razetime

both alt keys

Adám

Huh, doesn't happen for me on Firefox.

Razetime

the mac Alt/Option setup messes with some shortcuts

Adám

It should be Ctrl+Alt+x on Mac.

Razetime

5:16 AM

ah yes

that works

@Adám publish meaning put it on greasyfork?

Adám

@Razetime Or just on GitHub.

Razetime

it's on github, so I'll just publish to greasyfork for a single click install

Adám

Wait, there's something wrong with your script.

Razetime

ok what's happening

Adám

TM detects them when one clicks Raw, even from Gists. But not yours.

Razetime

5:22 AM

any console messages?

hmm I'll see

yeah that is strange

@Adám try it now

Adám

@Razetime Yes!

What did it?

Razetime

needs a .user.js extension

Adám

      ]state
Operating system is Debian GNU/Linux 10 (buster)
APL interpreter is 64-bit Dyalog 18.0.38756.0 Unicode
Server is Jarvis 1.7.1
TryAPL version is 3
Expressions may run for up to 10 seconds
Workspace used: 2 / 512 kilobytes

This is so much fun.

Razetime

I made a small adjustment

Adám

And I noticed a bug in TryAPL in the above.

Razetime

5:37 AM

it disables the button till the request is recieved

so now it shouldn't be spammable

Adám

Good idea. We do the same on TryAPL.

Now, if the script lived in a GitHub repo (or on Greasyfork) it would auto-update…

Razetime

cool

a github repo with a single file?

Adám

Sure, or a repo with all your userscripts.

Bubbler

(single-file repo is perfectly fine)

Razetime

huh alright

Bubbler

5:43 AM

> Workspace used: 2 / 512 kilobytes

really?

Adám

Really that 2 kB are missing or that we give you 512 kB?

Bubbler

Both

Adám

      ns←⎕NS⍬
      ⎕SIZE'ns'
2032

Bubbler

though for the latter I probably shouldn't use TryAPL for larger data

Adám

So you think it is too little?

Bubbler

5:46 AM

Not much of a problem, just surprised at the number

Probably I'm too fed up with Gitpod giving me 12GB RAM for free

Adám

OK, but TryAPL isn't for any sort of serious work. If you're using multiple arrays with tens of thousands of complex numbers each, then you're probably ready to move to a full APL system.

Bubbler

Yeah, I guess so

Adám

Another reason to keep it low is that we don't keep your state on the server. Rather we send it back to the client between every statement you execute. So if your state is too large, you'll begin noticing a slowdown, and see heavy data usage.

Razetime

Made a repo

Greasyfork

Bubbler

      {⎕IO←0⋄⎕UCS(16⊥⊢)⌺(⍪2 2)⊢⍵⍳⍨⎕D,⎕C⎕A} '7468697320697320612068657820737472696e67'
this is a hex string

Ooh, perfect

Razetime

5:58 AM

the good thing is that this doesn't interfere with the bot either

Adám

Yeah. But the best is the preview, imo.

Bubbler

      ⋄ +/ 1 2 3
6

Razetime

      ⊂⊂⍬
┌──┐
│┌┐│
││││
│└┘│
└──┘

Adám

@Bubbler You don't need the diamond. Old habit?

Bubbler

QAing

Adám

6:01 AM

@Razetime Future idea: select expression (on any website) and press some key combo to copy APL result to clipboard.

This would help in composing emails in a web client (say Gmail) and allow you to use APL in spreadsheets like Google Docs…

Razetime

that shouldn't be hard

Adám

APL Wiki could do with an "Enter APL expression here" input field…

Razetime

cool, who maintains APL wiki?

Bubbler

@Adám There must be some indicator for "in progress" and "complete" for that

Razetime

ok so context menu stuff is in a weird state on both chrome and ff

Adám

6:06 AM

@Razetime Mostly me, these days.

@Razetime Yeah, nobody seems to really care about that.

@Bubbler cursor:progress until done.

Razetime

shouldn't be hard to add an execute box near the search bar

@Adám ok, so I'm thinking of a hidden button with the same Alt-X keybind

Adám

@Razetime Yeah. That's how I do various shortcuts on APLcart.

Adám

6:31 AM

@Razetime I'm not sure it needs to be on every page. The front page is probably enough.

Razetime

cool

I'll ttyl

Adám

○/

Romilly Cocking

8:30 AM

@Adám I just discovered (slow creature that I am) that TryAPL now lets you run code from Jupyter Notebooks!

So, with minor tweaks, undoing my splits for multi-line dfns, and removing )save and )copy, I can run my MENACE code in TryAPL

Adám

@RomillyCocking Yes. There are still limitations in the support (well, there always will be), but our plan is to add more functionality over time. E.g. we'd like to be able to draw graphs and render HTML.

Romilly Cocking

Amazing

Adám

@RomillyCocking TryAPL supports multi-line dfns.

In fact, it supports tradfns too now.

Romilly Cocking

Really outstanding work. I have a flood of notebooks planned, some of which you might want to add to the site.

Adám

It just doesn't have an easy input method for them (yet, we do have that planned!) but when they are inside notebooks, it should just work.

Romilly Cocking

8:34 AM

The online docs are ood:
Limitations
Function and Operator definitions must be single-line and either tacit or dfns.

Adám

Yeah, that's for sanity due to the lack of an input method. Try this!

The plan is that Alt+Enter will insert a line break and tab indent rather than immediately executing, and then when your "block" is ready, you press Enter to define the whole thing.

Romilly Cocking

So the *only* things I need to fix in the MENACE notebooks are
removing )save and )load, and
finding some way to chain to the next notebook without losing session data.

*)copy, not )load

Adám

@RomillyCocking That shouldn't be a problem. Your notebook can link to https://tryapl.org/?notebook=url_of_next_in_series

Romilly Cocking

Wow. I'm hoping to get chapter 8 finished tomorrow, at which point the series is complete.

I'll ping you here when it is. If you have time to take a look, I'd love feedback and your opinion as to whether it's worth doing a PR to add the notebooks to the site.

Adám

Well, we can't exactly accept PRs because it is a private repo, but feel free to email tryapl@dyalog.com with such suggestions.

Hm, now I think of it, notebooks should probably begin with a clean slate by default, and require ?clear=no to prevent that.

Romilly Cocking

8:53 AM

I thought RP suggested PRs in one of the Dyalog videos. Sorry if I got the wrong end of the stick. I'll email when the notebooks are cooked :)

Adám

Ah, PRs against our Jupyter Notebook collection. However, these are not automatically shown on TryAPL.

MENACE sounds like it would fit into the "Further Explorations" category, though.

Martin Janiczek

10:35 AM

@Adám I've found something. When I )load isolate, stuff generally works. When I 'IÏ'⎕CY'isolate', it gives me the errors.

Adám

@MartinJaniczek Oh, of course. You should copy all of the workspace in with ⎕CY'isolate'

Martin Janiczek

Yeah I was just battling with being unable to do )load in a tradfn, and ⎕LOAD doing weird things (stopping execution of the rest of fn?). WIll try ⎕CY'isolate'

Also, leftargs∘process IÏ data doesn't work and {leftargs process ⍵} IÏ data does

Adám

Right, I just realised the other day that it must be awfully confusing that "load" is a destructive action (it removes all your stuff and replaces it with something else).

Martin Janiczek

@MartinJaniczek (⍎VALUE ERROR)

@Adám Oh yes. Somebody told me about ⎕CY after I complained about )load :D

But it's me being a CS person taking their assumptions to APL from other languages

module systems and whatnot

"oh this must be like import elsewhere". nope

Adám

It isn't APL terminology per se, but rather just ancient terminology. You load a cassette into a tape player, right?

And that "obviously" implies removing the existing tape.

Martin Janiczek

10:42 AM

@MartinJaniczek OK 'works' was a strong word. I can get rho of the result but trying to print the result results in FUTURE ERROR: VALUE ERROR.

@Adám Makes sense when you put it that way!

Adám

(Yeah, and if you want something from that tape on this tape, then you've got to copy it.)

Martin Janiczek

@MartinJaniczek (I've tried to go back to a working state, and go in steps: GoSerial, GoChunkedSerial, GoParallel, GoChunkedParallel. I'm in GoParallel right now.)

Adám

Similarly, APL uses "off" instead of "exit" because in the old days, there was no OS you'd quit to. Rather, you log off the mainframe, or maybe even turn it off altogether.

I'll ask Morten to come have a look when I see him online. It is his partner's birthday today, so we'll see when he appears…

Martin Janiczek

@Adám No worries, no rush!

It's all just an optimization anyways. The program works, this is just an experiment in how easy it would be to parallelize.

Adám

@MartinJaniczek It should be very easy. We're probably missing something fundamental. Oh, btw, did you try to compute something trivial in parallel?

Martin Janiczek

10:52 AM

@Adám The future error (when trying to print the result) happens even if the process function is {(≢⍺) (≢⍵)}

Oh but it's a different one: `FUTURE ERROR: 86: COMMUNICATIONS FAILURE 1119 ERR_CLOSED : Socket Closed while
receiving:`

I'll try restarting my RIDE.

Adám

It uses network communications. Did you give APL permission to use the local network?

Martin Janiczek

I'm not sure how to do that. I don't have any "Little Snitch" or other firewalls that I'd know of (I'm on a Linux machine)

Stuff generally doesn't ask me for permissions like a Windows box would, and generally works

Adám

Hm, so programs can use the network by default?

Martin Janiczek

Yes

After restarting RIDE and Dyalog process itself I'm back to

x
FUTURE ERROR: 6: VALUE ERROR: {leftargs process ⍵}: iEvaluate[13] (,⍕(⍕rc),': ',
(0⊃res),{(⍵∨.≠' ')/': ',⍵}1⊃res,'' '')iSpace.qsignal rc
      x
      ∧

I'm doing:

process←{(≢⍺) (≢⍵)}
⎕CY 'isolate'
data←↓(⍉↑lengths paddings readstarts)
leftargs←lines_file allfields wave namespace ⍝ needed for isolates: they don't share scope
x←{leftargs process ⍵} IÏ data

I'll try just copypasting some of the delay examples from the isolates doc PDF

Adám

@MartinJaniczek Btw, depending on the size of data, removing the parenthesis can give you a significant speed-up.

Martin Janiczek

10:58 AM

@Adám I just noticed the parentheses when copypasting this here :D

Could be removed yeah...

But how does it speed up the program? Fusion of functions? idiom recognition by the interpreter?

Adám

Yes. ↓⍉↑ becomes a single token and doesn't actually do the three steps.

Martin Janiczek

@Adám Lovely

      ⎕CY'isolate'
      ⎕DL IÏ 3 3 3 3
3.003719 3.003125 3.003297 3.00356

OK at least something works.

Is it possible that doing the ⎕CY'isolate' inside the tradfn each time I run it, might be the culprit?

(Spawning multiple servers and such)

Adám

The copying itself shouldn't matter.

As long as you're not doing that copy in a function that is in the middle of being parallel-processed.

Martin Janiczek

No :) Not inside process.

Might file IO (⎕MAP) inside the parallelized fn be problematic?

Inside process I need to read a chunk of a file, ⎕JSON it and process that

Adám

@MartinJaniczek I don't know. I wouldn't think so.

@MartinJaniczek Don't get offended, but does process return a result? It is a tradfn, right?

Martin Janiczek

11:07 AM

process is a multi-line dfn

well, right now it's {1} and it still doesn't work

Adám

:-(

Martin Janiczek

I can't remember what exactly did I do last night that it worked on the small-sized argument :))

x←{leftargs process ⍵} IÏ data ⍝ FUTURE ERROR: 6: VALUE ERROR (when printing x)
x←{process ⍵} IÏ data ⍝ FUTURE ERROR: 6: VALUE ERROR (when printing x)
x←process IÏ data ⍝ 1 1 1 1 1 1 1 1 1 1 (when printing x)

Maybe dfns aren't allowed with isolates?

x←leftargs∘process IÏ data ⍝ ⍎VALUE ERROR (immediately)

x←(1∘process) IÏ data ⍝ 1 1 1 1 1 1 1 1 1 1 (when printing x)

lines_file←'just a string'
x←(lines_file∘process) IÏ data ⍝ ⍎VALUE ERROR (immediately)

x←('abc'∘process) IÏ data ⍝ ⍎VALUE ERROR (immediately)

...strings nor single characters are allowed, seems to me.

⍝ minimal example
⎕CY'isolate'
⎕←(42∘{1}) IÏ 1 2 3 4 5 ⍝ works
⎕←('a'∘{1}) IÏ 1 2 3 4 5 ⍝ doesn't

dzaima

11:44 AM

@MartinJaniczek I would guess that's due to isolate not parsing derived operators and doing something like stringifying. e.g. with boxing off, entering both 4∘+ and '4'∘+ will print an equal representation (minus whitespace); also see that ('4'∘+) IÏ 1 2 works

(i.e. you definitely want the operand of IÏ to be a complete function, not some derivation, even if that means just wrapping it in {(…) ⍵})

Martin Janiczek

@dzaima Hmm, yes that helps

{'a' {1} ⍵} IÏ 1 2 3 4 5

dzaima

this makes Dyalog(s) use all the processor forever. ¯\_(ツ)_/¯

Martin Janiczek

Hm, yeah. But then I have to make my multi-line dfn into a one-line dfn, so that I can inline it into the {...} IÏ 1 2 3 4 5`? Or maybe tradfn would work?

dzaima

@dzaima ah, i assumed it'd make some effort to copy things over, but it does not. And f in isolates context happens to be the function itself, so it's just infinite recursion

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