Jürgen, Thank you, I had forgotten that ISO included the Rank operator!
Jay. On Fri, 24 Sept 2021 at 19:27, Dr. Jürgen Sauermann <mail@jürgen-sauermann.de> wrote: > > Hi, > > if we look at the rank operator in ISO APL (which is not present in IBM > APL 2) then they > define an operation "conform" which reads: > > *conform: *The shape of a result is the frame of the argument (relative > to the cells to > which the function applies) catenated with the shape of the individual > results produced > by applying the function to the individual cells. If the results do not > agree in shape > they are brought to a common shape as follows: > If the ranks differ, they are brought to a common maximum rank by > reshaping each > individual result to introduce leading unit lengths. > If the individual shapes differ (after being brought to a common rank), > each is brought > to a common shape by using take on each individual result, using as the > argument > to take the shape which is the maximum over the shapes. > > Even though ISO defined this operation only for conforming the argument > of the rank operator, > it seems reasonable to me to use it also for disclose as opposed to > using a different operation > to conform the argument of disclose. In particular since the > "deficiency" of the arguments (i.e. > differing ranks of the items) is exactly the same in both cases. > > Best Regards, > Jürgen > > > On 9/24/21 7:30 PM, Jay Foad wrote: > > Apart from compatibility with Rank (which didn't exist in Dyalog > > before 14.0), why do you think adding leading ones to the shape is > > "obvious"? Why not trailing ones, for example? > > > > Jay. > > > > On Fri, 24 Sep 2021, 15:48 Elias Mårtenson, <loke...@gmail.com > > <mailto:loke...@gmail.com>> wrote: > > > > Fair enough. That said, I think dzaima/APL implements it. As does > > KAP now. > > > > It's also a pretty obvious implementation, and the behaviour > > orthogonal, instead of having a special case for scalars. > > > > Regards, > > Elias > > > > On Fri, 24 Sept 2021 at 22:35, Jay Foad <jay.f...@gmail.com > > <mailto:jay.f...@gmail.com>> wrote: > > > > Elias, > > > > This was an extension to Mix in Dyalog 14.0 > > (http://docs.dyalog.com/14.0/Dyalog%20APL%20Release%20Notes.pdf > > <http://docs.dyalog.com/14.0/Dyalog%20APL%20Release%20Notes.pdf> > > p22) > > inspired by the way the Rank operator assembles results with > > differing > > ranks. I'm not aware of any other APL2-like APLs implementing this > > extension. > > > > Jay. > > > > On Wed, 22 Sept 2021 at 14:20, Elias Mårtenson > > <loke...@gmail.com <mailto:loke...@gmail.com>> wrote: > > > > > > The following expression should work, if I'm reading the ISO > > spec correctly: > > > > > > ⊃ 3 (1 2) (2 2 ⍴ 0 1 2 3) > > > > > > It does work on Dyalog, and gives the expected result. > > > > > > Regards, > > > Elias > > >
