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JuliaApproximation / FastTransforms.jl

:rocket: Julia package for orthogonal polynomial transforms :snowboarder:
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Potentially suboptimal performance in r2r transforms? #189

Open jishnub opened 1 year ago

jishnub commented 1 year ago

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?

MikaelSlevinsky commented 1 year ago

I guess it could be worth benchmarking, though it feels more like an FFTW issue to me.