Utilities for OpenFst --------------------- Benoit Favre <benoit.favre@lif.univ-mrs.fr> released under Apache License Version 2.0 This is a set of useful programs for manipulating Finite State Transducer with the OpenFst library. * fstcompile-nolex [-t]: compile an acceptor [transducer], generate symbol lexicons on the fly and save them with the fst. Useful for quick hacks on a single fst. * fstcompose-maplex <fst1> <fst2>: compose after mapping symbol tables (for use with fstcompile-nolex which generates different symbol tables) fst1 or fst2 can be "" (empty string) which means stdin. * fstminimize-transducer: encode input/output, rmepsilon, determinize, minimize and decode in one pass. * fstdeterminize-tc-lex: keep the best output for each input sequence in a transducer using determinization in the (Tropical, Categorial)-Lexicographic semiring. See "Efficient Determinization of Tagged Word Lattices using Categorial and Lexicographic Semirings", by Izhak Shafran et al, ASRU 2011. * fstsuperfinal-noepsilon: add a superfinal state without adding epsilon arcs * fstoracle <fst1> <fst2>: compute the shortest distance alignment between two transducers * fstcompose-specials <fst1> <fst2>: compose two transducers using special <phi>, <rho> and <sigma> transitions. <sigma> can replace any input symbol; <rho> is like sigma but only if no other path can be followed; <phi> is an epsilon transition which can be followed if no other transition matches an input symbol. Note that lexicons from the two fsts are mapped. fstprint sentence.fst: 0 1 the 1 2 boy 2 3 is 3 4 here 4 fstprint model.fst: 0 0 <rho> <eps> 0 1 boy XXX 1 2 is YYY 2 2 <rho> <eps> 2 ./fstcompose-specials model.fst < sentence.fst | fstprint 0 1 the <eps> 1 2 boy XXX 2 3 is YYY 3 4 here <eps> 4 * fstposteriors: compute arc-level posterior probabilities from an automaton where weights are -log probs in the tropical semiring. * fstprint-nbest-strings <n>: compute nbest and print string of input/output symbols (or input if input == output) --- less useful / non-working stuff --- * add-tags <dict>: generate a tagging transducer from a word acceptor according to a tab-separated, one-word-per-line tag dictionary * ngram-expand: expand transducer so that each arc has a fixed context of up to n-1 arcs (so called ngramize) -- non functional at this time