So, if I understand your sliding window explanation right, would the distance between two strings X and Y then be a feature vector of all the NCDs of its window

So, if I understand your sliding window explanation right, would the distance between two strings X and Y then be a feature vector of all the NCDs of its windows? Kind of reminds me of auto correlation :) Also, just a note about your NCD formula, if C(xy) is the compressed size of the concatenation of x and y, then I would recommend also trying (C(xy)+C(yx))/2 for that term, because a lot of compressors don't compress xy the same as yx, and you probably want your distance to be symmetrical.