Outer Product (`∘.f`)¶

Syntax¶

X ∘.f Y

f is a dyadic scalar function. X and Y are arrays.

Applies f to every pair of elements, one from X and one from Y. The result shape is (⍴X),(⍴Y), with element [i;j] equal to X[i] f Y[j].

Multiplication table:

      1 2 3 ∘.× 1 2 3 4
1 2  3  4
2 4  6  8
3 6  9 12

Addition table:

      1 2 3 ∘.+ 10 20 30 40
11 21 31 41
12 22 32 42
13 23 33 43

Equality table (character example):

      'abc' ∘.= 'abba'
1 0 0 1
0 1 1 0
0 0 0 0