Non-Linearity Index   <<   >>

 
f←{
  u← ○ ? (⍵,⍺) ⍴ ⌈⍵*÷⍺
  x∘← u ⌷⍨ ⊂ ?⍵⍴⍵    
  y∘← u ⌷⍨ ⊂ ?⍵⍴⍵
  1 1 cmpx 'x⍳y'  
}
   ⎕←t3← 3 f¨ 1e3 × 2*⍳6
0.00803906 0.033125 0.122813 0.472 1.919 7.426
   2 ÷⍨/ t3
4.12051 3.70755 3.84326 4.06568 3.86972

   ⎕←t←(⊂⍬) f¨ 1e3 × 2*⍳6
0.0000480957 0.000119995 0.00027832 0.000617188 
      0.00128027 0.00286328
   2 ÷⍨/ t
2.49492 2.31943 2.21754 2.07437 2.23646

   t3 ÷ t
167.147 276.053 441.263 764.759 1498.9 2593.53