hix←{
  X←⍵
  Z←(≢⍵)⍴¯1
  c←{⊂⍵}⌸ ⍺⍺ ⍵
  Z ⊣ {0 ⊣ Z[⍵]←⍵[xix X⌷⍨⊂⍵]}¨ c
}

   hf←{3⊥⎕av⍳⍵}

   x← ⍕¨ ?1e3⍴1e5
   cmpx 'xix x' 'hf¨ hix x'
  xix x     → 3.36E¯4 |    0% ⎕⎕⎕
  hf¨ hix x → 3.59E¯3 | +968% ⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕

   ⎕←t←{x∘←⍕¨?⍵⍴1e5 ⋄ 1 1 cmpx 'hf¨ hix x'}¨ 1e3×1 2 4 8 16
0.00353516 0.00584766 0.009875 0.0158438 0.0260781

   2 ÷⍨/ t
1.65414 1.68871 1.60443 1.64596