All-distances-twice rows

Consider a tone-row f and determine the list (d1,…,d12) of distances between consecutive tones of f, i.e. di is the distance of f(i) and f(i+1) for i∈ {1,…,11} and d12 the distance of f(1) and f(12). If each distance from {1,…,6} occurs exactly twice in (d1,…,d12), then f is an all-distances-twice row.
Database on tone rows and tropes
harald.fripertinger "at" uni-graz.at
January 2, 2019