19. The computer readable non-transitory storage medium of claim 17 , at least one edge of the plurality representing more than one transition of the plurality.
19. The computer readable non-transitory storage medium of claim 17 , at least one edge of the plurality representing more than one transition of the plurality. 20. The computer readable non-transitory storage medium of claim 19 , the instructions further comprising instructions to: assign a weight to each edge between the two buckets of the first plurality, the weight representing a volume of transitions between the two buckets.