Viewing profile — mlochbaum

This is one of the best uses I've found for Singeli[0]. Here's how I implemented an AVX2 transpose kernel similar to that in transpose_Vec256_kernel, for generic type and vector/ke…

It's possible to get O(N^(3/2)/log N) in an ordinary interpreter with some changes to the code, assuming linear-time ~ with hashing. The idea is to leave the primes in ⍵ and stop w…

That's not O(N log log N), it's more like N^2. Prime sieves are hard to implement well with immutable arrays for obvious reasons; there are some cool methods but they're definitely…

It's very strange to see handwriting lumped in with typewriting, to be described as limited relative to screens! Iverson notation was a 2D format (both in handwriting and typeset p…

I don't think this really describes neon_prefixsum_fast as a whole? The algorithm does use a Hillis-Steele sum on sums of 4 values, but each of these is computed with a sequential …

More on not being able to find π, as I'm piecing it together: given only the field structure, you can't construct an equation identifying π or even narrowing it down, because if π …

I was interested in how it would make sense to define complex numbers without fixing the reals, but I'm not terribly convinced by the method here. It seemed kind of suspect that yo…

Ooh, I've run into this one before! I'm a big fan of interval index[0], which performs a binary search, so Josh's suggestion is the one I prefer as well (the implementation might s…

It was the subject of quite some debate, see "Panel: Is J a Dialect of APL?" at http://www.jsoftware.com/papers/Vector_8_2_BarmanCamacho.pdf . Ken and Roger backed off this stance …

I think the article expresses no position. Most source code for array languages is not, in fact, inspired by APL. I encourage you to check a few random entries at [0]; Kap and Apri…

Dunno why electroly is dragging me into this but I believe you've misread the article. When it says "His languages take significantly after APL" it means the languages themselves a…

It looks like a weirdo C convention to APLers too though. Whitney writes K that way, but single-line functions in particular aren't used a lot in production APL, and weren't even p…

Ordinarily I'd make fun of the Germans for giving such an ugly name to a nice concept, but I've always found "comfortable" to be rather unpleasant too (the root "comfort" is fine).…

It's just. So gross. Say it. Sudden interruption of slime coming up your throat. Like walking out the door into a spiderweb. Alphabetically I was mistaken but in every way that mat…

Well, do you know how it works? Don't judge a book by its cover and all. Although none of these are entirely aiming for elegance. The first is code golf and the other two have some…

The point that the article is addressing (but you have to ignore the image and study the equations to see this!) is that this sort of shifting can't equalize everything. In the spa…

And the reason +˝ is fairly fast for long rows, despite that page claiming no optimizations, is that ˝ is defined to split its argument into cells, e.g. rows of a matrix, and apply…

The relevant operations for matrix multiply are leading-axis extension, shown near the end of [0], and Insert +˝ shown in [1]. Both for floats; the leading-axis operation is × but …

To be clear, you are referring to the preface to "An Introduction to Array Programming in Klong", right? Having just checked it, I find this to be a very strange angle of attack, b…

Oddly enough, the biggest mistake in how I presented BQN early on was thinking only APL insiders would be interested, when in fact the APLers went back to APL and people who hadn't…

Search for "teaching" at https://aplwiki.com/wiki/APL_conference . I count at least five papers about teaching non-APL topics using APL. The language is not only possible to read, …

"already": APL dates back to about 1966, and even K from 1993 predates Numpy and Julia. But yes, we do not live in caves and are familiar with these languages. Klong has even been …

Author of BQN here, I agree with how section "What about APL?" describes the APL family as not fundamentally better (although details like indexing are often less messy). I outline…

The queue method is popular, but there's a much faster (branch-free) and in my opinion simpler way, known as the van Herk/Gil-Werman algorithm in image processing. It splits the in…

I'd forgotten about patience sorting! Not that I was ever exactly familiar with it. JesseSort seems nearly identical, except that it allows insertion to either side of the lists, t…