JuliaApproximation / JuliaApproximation/FastTransforms.jl

Potentially suboptimal performance in r2r transforms?

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Dominant language
Julia
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281
Forks
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No merged PRs in 30d

Description

Currently, the Chebyshev plans internally use FFTW.r2r plans, eg.
https://github.com/JuliaApproximation/FastTransforms.jl/blob/59774abd59061e26ee18e267d82963f8a87fd32a/src/chebyshevtransform.jl#L37-L43
However, from what I understand after reading Steven G. Johnson's post on discourse, the r2r transforms are not as optimized as the r2c ones, and are not recommended over the alternatives. I wonder if a rewrite of the r2r transforms (here or elsewhere) might improve performance?

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Research direction

Start with the Chebyshev plan construction in src/chebyshevtransform.jl around lines 37–43, then read the linked Discourse discussion about FFTW.r2r performance. Benchmark the current r2r-based plans against the alternatives discussed and determine whether a rewrite is warranted. Done means a validated performance improvement with the relevant transform behavior preserved.

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Assessment

Tech stack
julia
Domain
performance
Issue type
Refactor
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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