https://gist.github.com/chrispsn/af6844b80687462814fc39d4b97399a6
may be of interest
On Wed, 13 Jul 2022, Raul Miller wrote:
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
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