Tootfinder

"Vancouver has 22 civic libraries. Victoria has 12. The streets of these two cities, however, have well over 1,000 unincorporated “little libraries”. You’ve seen them, of course. Those quaint little bird-house structures, placed along sidewalks, usually with a glassed-in front to keep the contents safe from the elements. Inside these little boxes there is always the oddest selection of books, and almost always something that will pique your interest. "

Permutation-Avoiding FFT-Based Convolution
Nicolas Venkovic, Hartwig Anzt
https://arxiv.org/abs/2506.12718 https://arxiv.org/pdf/2506…

Permutation-Avoiding FFT-Based Convolution
Fast Fourier Transform (FFT) libraries are widely used for evaluating discrete convolutions. Most FFT implementations follow some variant of the Cooley-Tukey framework, in which the transform is decomposed into butterfly operations and index-reversal permutations. While butterfly operations dominate the floating-point operation count, the memory access patterns induced by index-reversal permutations significantly degrade the FFT's arithmetic intensity. In practice, discrete convolutions are oft…