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Adám Brudzewsky

@abrudz.bsky.social

28 followers 4 following 5 posts

Orthodox Jew working full time as APL programmer and Head of Language Design at Dyalog Ltd.

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Adám Brudzewsky @abrudz.bsky.social · 05/02/2026

And I'm number three.

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Adám Brudzewsky @abrudz.bsky.social · 11/11/2025

Much better, but as a professional APLer, I would have written `(100<(+/÷≢)sym(¯3↑⊢)⌸price)/∪sym` which is only 23 tokens. Maybe Python's 26 tokens more doesn't sound like much, but that's over 200% as many tokens!

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Adám Brudzewsky @abrudz.bsky.social · 10/11/2025

That said, what does "compute a weighted 3-period moving average by symbol, filtering for symbols where average is greater than 100" even mean? Where the average *at some point* was greater than 100? Surely, a moving average is a list, and I don't see how to meaningfully filter by lists > 100.

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Adám Brudzewsky @abrudz.bsky.social · 10/11/2025

I'm a confused about example 2. I don't know Q or Python, but the APL code seems iffy even if `,\\` is just a typo, as it doesn't even refer to the symbols; `(⍳3)×¨` needs no `¨` unless you meant `∘×¨`; `(3÷+/⍳3)×` is just `0.5×`; `{⍵/⍨100<+/⍵}¨` filtes the raw data instead of the symbols; etc.

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Adám Brudzewsky @abrudz.bsky.social · 21/01/2025

It really should say "given a square numeric matrix".

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