Performance issues

[carkat]

https://codeberg.org/CptJimKirk/aoc/src/commit/da2d8826e9f9356fde81a350b9d3817312a47999/cl/apl/15.apl#L54

Over a 1000 1000⍴0 array, apply a function to windowed regions defined by

{{↓(⊃⍵)+⍤1⊢↑,⍳1+⊃|-/⍵}1↓¨⍵}

where ⍵ is (x1 y1)(x2 y2) integer pairs of coordinates.

In Dyalog this takes 4 seconds. In April this is taking well over 15 minutes. I don't know if the windowed regions, applying the function, or the sheer size of the array is the source of the slow down. But something is dragging.