In-situ bit-reversed ordering for Hartley transforms
O. Buneman · IEEE Transactions on Acoustics Speech and Signal Processing · 1989
The Johnson-Burrus method of in situ ordering for FFTs is applied to fast Hartley transforms. It amounts to tying together two consecutive butterfly operations, involving eight real data, swapping some of their results. Pre- and postpermutation can thereby be avoided. The identification of negative indexes, significantly in Hartley transforms, is nontrivial but easily resolved.>