The context costs between f i and all the units in the preselection list of the phonetic context ρ i are computed and the M units with the best context cost are selected: The feature costs between f i and the units in U i are then computed and the N units with the best target cost are selected: The unit sequence u verifying: is determined using a classical Viterbi search.
for each position i, the N 2 concatenation costs between the units in U i and U i+1 need to be computed.