JuliaLang/julia

broadcasted bit operations are not optimized for BitArrays

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#36,168 opened on Jun 5, 2020

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 (1 comment) (3 reactions) (0 assignees)Julia (5,773 forks)batch import
arrayshelp wanted

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Description

Base has methods that efficiently perform bitwise operations over BitArrays by performing the operations 64 bits at a time (i.e. on each "chunk"). This is much faster than looking up and operating on individual bits. This machinery is used for map and map!, but it does not appear to be leveraged for broadcasting bitwise operations over BitArrays. It would be nice to do so (at least for BitArrays of the same size, which is a common use case). If this is worth doing, I would be willing to attempt a PR (it would be my first).

Contributor guide

Research direction
Study the existing optimization for map and map! on BitArrays (in base/bitarray.jl) and apply the same chunk based approach to broadcasted bitwise operations.
Tech stack
julia
Domain
backend
Issue type
Performance
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
JuliaGit
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70