// fstext/remove-eps-local.h
  
  // Copyright 2009-2011  Microsoft Corporation
  //                2014  Johns Hopkins University (author: Daniel Povey)
  
  // See ../../COPYING for clarification regarding multiple authors
  //
  // Licensed under the Apache License, Version 2.0 (the "License");
  // you may not use this file except in compliance with the License.
  // You may obtain a copy of the License at
  //
  //  http://www.apache.org/licenses/LICENSE-2.0
  //
  // THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  // KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
  // WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
  // MERCHANTABLITY OR NON-INFRINGEMENT.
  // See the Apache 2 License for the specific language governing permissions and
  // limitations under the License.
  
  #ifndef KALDI_FSTEXT_REMOVE_EPS_LOCAL_H_
  #define KALDI_FSTEXT_REMOVE_EPS_LOCAL_H_
  
  
  #include <fst/fstlib.h>
  #include <fst/fst-decl.h>
  
  namespace fst {
  
  
  /// RemoveEpsLocal remove some (but not necessarily all) epsilons in an FST,
  /// using an algorithm that is guaranteed to never increase the number of arcs
  /// in the FST (and will also never increase the number of states).  The
  /// algorithm is not optimal but is reasonably clever.  It does not just remove
  /// epsilon arcs;it also combines pairs of input-epsilon and output-epsilon arcs
  /// into one.
  /// The algorithm preserves equivalence and stochasticity in the given semiring.
  /// If you want to preserve stochasticity in a different semiring (e.g. log),
  /// then use RemoveEpsLocalSpecial, which only works for StdArc but which
  /// preserves stochasticity, where possible (*) in the LogArc sense.  The reason that we can't
  /// just cast to a different semiring is that in that case we would no longer
  /// be able to guarantee equivalence in the original semiring (this arises from
  /// what happens when we combine identical arcs).
  /// (*) by "where possible".. there are situations where we wouldn't be able to
  /// preserve stochasticity in the LogArc sense while maintaining equivalence in
  /// the StdArc sense, so in these situations we maintain equivalence.
  
  template<class Arc>
  void RemoveEpsLocal(MutableFst<Arc> *fst);
  
  /// As RemoveEpsLocal but takes care to preserve stochasticity
  /// when cast to LogArc.
  inline void RemoveEpsLocalSpecial(MutableFst<StdArc> *fst);
  
  
  }  // namespace fst
  
  #include "remove-eps-local-inl.h"
  
  #endif