Some embodiments provide a method of propagating a first function, which is
defined over a first state, to a second state in a multi-state space. The method
identifies vectors to project from at least some points on the first state that
serve as locations of inflection points in the first function; where the vectors
are identified based on a model that allows penalizes measurements in certain directions
more than other directions. Based on the projected vectors, the method then computes
the second function from the first function.
