[The] nub is found by selecting the leading item, suppressing from the argument all items tolerantly [matching] it, selecting the next remaining item, and so on.

   uniq1  ← {1≥≢⍵:⍵ ⋄ (0⌷⍵)⍪∇⍵⌿⍨⍵≢⍤¯1 999⊢0⌷⍵}
   uniq1v ← {1≥≢⍵:⍵ ⋄ (⊃⍵)⍪∇⍵⌿⍨⍵≠⊃⍵}        ⍝ vector case

   uniq1 UD x←rand 666
1
   uniq1 UD 3/⍪x
1
   uniq1 UT 0
assertion failure
UT[4] assert 2.5≥(+⌿÷≢)2÷⍨/t←⍵ time¨1000×1 2 4 8:
     ∧
   t
0.0143438 0.0550937 0.214625 0.84
   2 ÷⍨/ t
3.84096 3.89563 3.9138