3 ms·

Very honest discussion of the results. I liked it. Would it be possible to use Futhark to rewrite the APL implementation instead of the Haskell one? That would

• Athas 7y ago
  > Would it be possible to use Futhark to rewrite the APL implementation instead of the Haskell one? That would make an interesting comparison. Sadly, from what I can see, the APL version makes use of so-called nested arrays in the 'words' function, specifically arrays of strings (this is different from multidimensional arrays). Futhark does not directly support nested arrays. A rewrite of the APL implementation would require using a quite different algorithm (or a nontrivial encoding). But my APL is a bit rusty, so I may be wrong.
  • ummaycoc 7y ago
    In my original version I didn't use a nested array of strings, but [Olzd](https://news.ycombinator.com/user?id=olzd https://news.ycombinator.com/user?id=olzd) pointed out a way you could do that and I added it as a theoretical first attempt (theoretical since it wasn't my first attempt, but would have been had I been better at APL). My first attempt did some stuff with subtracting items in an array from their neighbor. Now with info I got from [mlochbaum](https://news.ycombinator.com/user?id=mlochbaum https://news.ycombinator.com/user?id=mlochbaum) I have another version that uses windowed reductions. So those are three versions there; after that I just split it up just to see where that leads and that actually ends up feeling a lot like the Haskell / Futhark solution to me.