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Models Row by Column
dotc ←{↑ (↓⍺) ∘.(⍺⍺{⍺⍺/⍺ ⍵⍵ ⍵}⍵⍵) ↓(¯1⌽⍳⍴⍴⍵)⍉⍵} x←¯500+?13 19 11⍴1000 y←¯500+?11 23⍴1000 (x+.×y) ≡ x +dotc× y 1 (x-.≥y) ≡ x -dotc≥ y 1