What’s Going On with DIT/DIF III
We iterate this idea with phases p running from 0 to d-1. At the p’th phase, one is manipulating the p’th digit of f(m) and forming the d-1-p’th index of GN(k,f).
Thus starting with f(m) with binary labeling:
One ends up with GN(k,f) with totally reversed index scheme
Note that in recursive mode, one starts forming recursion with phase p=0 but first computations are done at phase p=d-1 where one is manipulating f(m) with highest binary index md-1 and forming GN(k,f) with binary index k0