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Sherlock9

 The APL Orchard

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Sherlock9
May 22, 2021 15:36
noice
Sherlock9
May 22, 2021 15:36
      {=/⍵:1⋄∨/0=⍵:0⋄>/⍵:0⋄+/(1,⊃⍵)×(∇⍵-1),∇0 ¯1+⍵}⍤1⊢↑⍳2⍴7
1 1 1 1  1  1   1
0 1 3 7 15 31  63
0 0 1 6 25 90 301
0 0 0 1 10 65 350
0 0 0 0  1 15 140
0 0 0 0  0  1  21
0 0 0 0  0  0   1
Sherlock9
May 22, 2021 15:06
I see, thanks
Sherlock9
May 22, 2021 14:56
But {+/⊃⍵}⍤0⊢⍳2⍴7 works fine
Sherlock9
May 22, 2021 14:55
{+/⍵}⍤0⊢⍳2⍴7 doesn't seem to work
Sherlock9
May 22, 2021 14:54
Does ⍤ rank work over something like ⍳2⍴7 which I think is an array of ragged arrays?
Sherlock9
May 22, 2021 14:51
This is probably hackier than necessary, but I think it works {=/⍵:1⋄∨/0=⍵:0⋄>/⍵:0⋄+/(1,(⊃⍵))×(∇¯1+⍵),∇0 ¯1+⍵} with ⍵≡2⍴k n for S(n, k)
Sherlock9
May 22, 2021 14:45
Maybe I shouldn't do ⍺ and ⍵ if I want to make a triangle of S(n, k)
Sherlock9
May 22, 2021 14:43
Hm, I'm writing a dfn for Stirling numbers of the second kind, which, after the base cases, is +/1 ⍺×((⍺-1)∇(⍵-1)),⍺∇⍵-1
Sherlock9
May 22, 2021 14:41
Assuming both ⍺ and ⍵ are numeric scalars
Sherlock9
May 22, 2021 14:40
Quick question how to do something like (⍺-1)∇⍵-1 in a dfn but something like ∇ (over) ¯1+⍺ ⍵ maybe
Sherlock9
May 18, 2021 18:29
Oh yeah that makes a lot of sense, thanks!
Sherlock9
May 18, 2021 18:13
Oh thanks
Sherlock9
May 18, 2021 18:01
Crossposting my question from the Discord server: How does this algorithm work? I'm having trouble parsing the train codegolf.stackexchange.com/a/158379/80214 The code: {0∊≢¨⍵:≢∊⍵⋄⌊/(≢.↑+∘∇↓¨)∘⍵¨1↓,⍳2 2} and the train: (≢.↑+∘∇↓¨)
Sherlock9
May 17, 2021 16:29
@xpqz Node 3 isn't connected to anything else yet
Sherlock9
May 17, 2021 16:10
Found it! An essay on partitions code.jsoftware.com/wiki/Essays/…
Sherlock9
May 17, 2021 15:57
inner_p=: 3 : 0
   if. y<.0 do.
     0
   elseif. 0 < y { memo do.
     y { memo
   else.
     y { memo =: memo y}~ -/+/inner_p"0 y+(2%~]*1-3*])(],:-)1+i.y
   end.
   )

partition=: 3 : 0
   memo=:1,y$0
   inner_p y
   )
Sherlock9
May 17, 2021 15:57
Got it!
Sherlock9
May 17, 2021 15:50
Oh it's < not <.
Sherlock9
May 17, 2021 15:44
inner_p=: 3 : 0
   if. y<.0 do.
     0
   elseif. 0 <. y { memo do.
     y { memo
   else.
     z =. -/+/"1 inner_p"0 y+(2%~]*1-3*])(],:-)>:i.y
     memo =: z y} memo
     z
   end.
   )

partition=: 3 : 0
   memo=:1,y$0
   inner_p y
   )
Sherlock9
May 17, 2021 15:43
Alright so the following J code doesn't work
Sherlock9
May 17, 2021 15:21
Yeah, I figured. I put some golfs in my code like ⍵≤0:⍵=0 but that's not as readable I suppose
Sherlock9
May 17, 2021 15:17
@rak1507 You can shorten ⍵-(2÷⍨⊢×1-⍨3×⊢) to ⍵+(2÷⍨⊢×1-3×⊢)
Sherlock9
May 17, 2021 15:16
And I'm not sure how J does recursion either
Sherlock9
May 17, 2021 15:16
Not sure how to do p[⍵]←... in J
Sherlock9
May 17, 2021 15:16
I've seen complaints about modified assignments to arrays and how they're handled (there is a massive bug, if I remember the complaints correctly), but at least Dyalog APL appears to have them
Sherlock9
May 17, 2021 15:15
The longer I work on this J translation, the nicer I think Dyalog APL is XD
Sherlock9
May 17, 2021 14:34
@rak1507 Ooh that's very nice, and it might work better with my attempted J translation
Sherlock9
May 17, 2021 14:04
Trying to convert it to J and I have no idea where the editor is XD
Sherlock9
May 17, 2021 14:03
Let me try to write it in APL-like syntax
Sherlock9
May 17, 2021 14:03
Using this one wikimedia.org/api/rest_v1/media/math/render/svg/…
Sherlock9
May 17, 2021 14:02
@rak1507 Yeah, that's where I got the inspiration too
Sherlock9
May 17, 2021 14:02
@rak1507 Oh that's interesting. Let me take a look
Sherlock9
May 17, 2021 13:40
First and most importantly, the purpose of this chatroom is to educate, first about the APL languages and descendants, and then about the historical context. But seeing as the main purpose is to educate, and not to squabble, please refrain from arguing so heatedly in this channel. The trouble is not the matter of the discussion, but the overtaking of the channel such that it is awkward to change the subject onto lighter matters of education as I have wanted to do now for an hour. I do not ask that you do not argue, merely that you both do so with awareness of the forum in which you are doin…
Sherlock9
May 17, 2021 12:13
See also Ramanujan en.wikipedia.org/wiki/Partition_function_(number_theory)
Sherlock9
May 17, 2021 12:13
Oh no I mean the number-theoretic partition function
Sherlock9
May 17, 2021 12:10
      partition 100000
DOMAIN ERROR
partition[8] ⊢m,←-/+⌿p⍤0⊢z
                   ∧
⍝ Found another limit
Sherlock9
May 17, 2021 12:07
      partition 6353
¯1.508503541E82
      partition 6352
3.466844567E81
Sherlock9
May 17, 2021 12:07
I do seem to have a bug
Sherlock9
May 17, 2021 12:04
Thinking of writing in k←⌈6÷⍨1+0.5*⍨1+24×⍵ and using ⍳k at end of z instead of the entirety of ⍳⍵ which adds a lot of extra lookups
Sherlock9
May 17, 2021 12:00
partition←{
    ⍵≤0:⍵=0
    m←⍬
    p←{
        ⍵≤0:⍵=0
        ⍵≤≢m:m[⍵]
        z←⍵+{2÷⍨⍵-3×⍵×⍵}⍤0⊢↑(⊢,-)⊂⍳⍵
        ⊢m,←-/+⌿p⍤0⊢z
    }
    r←p⍤0⊢⍳⍵
    m[⍵]
}
Sherlock9
May 17, 2021 12:00
Wrote the partition function in APL again, this time with memoization
Sherlock9
May 14, 2021 15:38
I thought I missed a release
Sherlock9
May 14, 2021 15:38
... Oh that'll do it
Sherlock9
May 14, 2021 15:37
Mostly rhetorical, just means I get to change versions
Sherlock9
May 14, 2021 15:36
How is it that I downloaded the Dyalog IDE all of 7 days ago and it gave me 18.0
Sherlock9
May 14, 2021 10:56
It premieres at 4 am for me
Sherlock9
May 13, 2021 22:06
This requires a great deal more thought than I am currently able to give it
Sherlock9
May 13, 2021 22:04
What I'm not sure about is whether the best syntax to keep is Haskell's currying from the function on the left to the right (or from right to left?) until it's taken enough arguments, or to keep to APL's on one argument on the left, one argument on the right.
Sherlock9
May 13, 2021 22:02
Am I off in my understanding that operators are functions that take other functions as parameters? Because Haskell does that just fine, if so