Is there a better way to get the first n powers of a matrix than {⍺≡≢⍵:⊃¨⍵ ⋄ ⍺∇⍵,+.×/2⍴¯1⌽⍵} ?

@rak1507 ^

Great news, thanks for the update @Adám :D

I overslept each morning and missed some sessions that I was looking forward to..

Great, now to watch em

@Marshall Am I correct in remembering this algorithm from your presentation on sub nanosecond searches?

@ab5tract No, you're probably thinking of binary search. Dyalog doesn't use quickselect as of 18.0.

@Marshall Thanks for clarifying. I guess I remember being so impressed with the results you were able to achieve that I blocked the fact that it was "just" binary search!

@Adám oh great thanks :)

cmc: implement ∩ in terms of ∪ and ~

@rak1507 umm, 3 bytes

Oh

:p

Are you sure?

@rak1507 passes ∧/{(?100⍴100) ((solution)≡∩) (?100⍴100)}¨⍳100000

got another 3-byter that's much cooler

Didn't think you could do better than ∪~~⍨∪~

@rak1507 hint

??

Alright I give up

my solution. CMC: find the "much cooler" version

Oh you're using other functions

I meant entirely with ~ and ∪

@rak1507 well, you're using ⍨

{(⍺∪⍵)~(⍺~⍵)∪(⍵~⍺)} works I guess

@rak1507 you can expand mine to a dfn with no extra chars too

fair point

I just watched Roger's talk on inverted tables from Dyalog '18. That was interesting.