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NumPy-style broadcasting in Futhark

(futhark-lang.org)
132 points zfnmxt | 1 comments | 17 Jun 24 10:38 UTC | HN request time: 0.205s | source
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stabbles ◴[18 Jun 24 07:01 UTC] No.40714856[source]▶
Somewhat confusing to see a matrix represented as an array of arrays, it will never be fast.
replies(1): >>40714907 #
tomsmeding ◴[18 Jun 24 07:08 UTC] No.40714907[source]▶
This is in the surface language only: Futhark's arrays must be "rectangular" (if you have an array of arrays, the subarrays are mandated to be equally-sized; this is statically checked in most cases, and when it can't, it becomes a runtime check), and thus they are represented as a single, actual multi-dimensional array.
replies(1): >>40716597 #
adgjlsfhk1 ◴[18 Jun 24 11:43 UTC] No.40716597[source]▶
imo that seems like some pretty weird semantics. how do you write an operation that needs to bundle together lists of different lengths?
replies(1): >>40717028 #
1. Athas ◴[18 Jun 24 12:29 UTC] No.40717028[source]▶
The best answer is that you probably don't want to use Futhark for that - it's a specialised, rather restricted language. There are ways to encode irregular arrays, but it's not even remotely as ergonomic as in other languages (it can be plenty fast, however). For a particularly simple example, see https://futhark-lang.org/examples/triangular.html

In the future, or in a future similar language, one might well imagine an ability to "box" arrays, like in APL, which would allow true "arrays of arrays" with no restrictions on sizes.