Signal processing
Mixed-radix digit reversal
Export an index permutation with both digits and their radix order reversed.
Your inputs
Start with an exampleYour result
Example resultAa — A small example of your colors.
How it works
Expand each source index in the supplied mixed bases. Reverse the digit/base order together; export source→destination and the inverse lookup.
With least-significant-first bases 2,3, source indices 0–5 map to 0,3,1,4,2,5. The inverse is 0,2,4,1,3,5.
Limits
2–64 per radix, at most 12 radices and product 4096. This explicitly defined mixed-base permutation is not generally its own inverse. The fixed-base reference describes ordinary digit reversal; the displayed formula extends it. No particular FFT kernel, memory-bank layout or library order is assumed.