Interval Index Domain Error

[paulmansour]

So interval index gives a domain error when there are duplicates in the left argument:

      1 2 3 3 4 5⍸2.5 3.5 4.5
DOMAIN ERROR
      1 2 3 3 4 5⍸2.5 3.5 4.5
     ∧

We can write a little idiom for domain error free ( in case of dupes) interval index:

      1 2 3 3 4 5{u←∪⍺ ⋄ ⍺⍳u[u⍸⍵]}2.5 3.5 4.5
1 2 4

Which I had to do while writing a percentile ranking function.

Obviously it is no big deal to use this snippet when needed, but is there perhaps a case to eliminate the domain error in this case?

[Jay|Dyalog]

Paul,

We've been discussing this recently and came to the same conclusion as you: Interval Index should work with empty intervals. This change will be implemented in version 18.0.

Jay.