Re: Potential problem in diadic iota (⍳) or in Pick (⊃)

[Dr . Jürgen Sauermann]

    Gentlemen,
      
      thanks, fixed in SVN 1334.
    
    Best Regards,
    Jürgen

On 8/7/20 4:33 PM, Kacper Gutowski wrote:

> On Thu, Aug
>       06, 2020 at 08:50:27PM -0400, Christian Robert wrote:
>       
> >      ∇z←(F fasteach) A;shp;vec;nub;res;idx
> >         
> >         shp←⍴A               ⍝ Shape and ...
> >         
> >         vec←,A               ⍝ ... ravel of arg.
> >         
> >         nub←∪ vec            ⍝ Vector of unique elements.
> >         
> >         nub←∪ vec            ⍝ Vector of unique elements.
> >         
> >         res←F¨nub            ⍝ Result for unique elts.
> >         
> >         idx←nub ⍳ vec        ⍝ Indices of arg in nub ...
> >         
> >         z←shp ⍴ idx ⊃¨⊂ res  ⍝ ... distribute result.
> >         
> >         ∇
> >         
> >       
>       
>       The problem is indeed in iota and it reminds me a similar problem
>       we had with an unique before.  For sufficiently big arrays, a
>       different algorithm is used where the left argument is sorted
>       beforehand to speed up searching; and something goes wrong there.
>       
>       
>       Smaller reproducer:
>       
>       
>             A←⌽⍳64
>       
>             B←⍳6
>       
>             B≡A[A⍳B]
>       
>       0
>       
>       
>       Should be 1, of crouse.
>       
>       
>       -k
>       
>       
>