Finite-state machines can be seen as graphs bearing transitions. These transitions can be symbols, couples of symbols, weighted couples or any other objects. Our filters however have been compiled once for all, so that the choice of a filter involves the choice of a transition type.Four types of filters can be built from WFST sources :
FSA, finite-state automata (deterministic and non-deterministic with epsilon)
WFSA, weighted finite-state automata
FST, finite-state transducers
WFST, weighted finite-state transducers
Once all the filters for these machines have been built, you can toggle between each type by doing (in src) either :
make install_fsa for FSA
make install_fst for FST
make install_wfa for WF(S)A
make install_wfst for WFST.