On Wed, Jul 13, 2022 at 4:23 AM Razetime <rraghu.11...@gmail.com> wrote: > The ngn/k version is much better for the K array model, and it's intended > as a nice and short description of the algorithm for nested lists.
Oh... yes... K is highly optimized for nested rank 1 lists of rank 1 lists -- J... not so much. J's rank winds up being mostly unnecessary overhead when emulating K's data structures. Still, if you wanted to represent matrices that way, here would be a way of implementing matrix multiplication on nested lists in J (not the part in parenthesis -- that could use some more work to approach "k-like notation" -- but that's just the starting matrices): +/@:>L:1 (<"1]1+i.4 3) *&.> L:0 1 (<"1]1+i.3 4) +-----------+-------------+---------------+---------------+ |38 44 50 56|83 98 113 128|128 152 176 200|173 206 239 272| +-----------+-------------+---------------+---------------+ It's a bit awkward, but hopefully not too distant from the K notation? (If I understand correctly, K's * gives the effect of J's *&.> for the sort of context illustrated here?). Thanks, -- Raul ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
