(r3) RelabelDoc < FST

FST Web>FstQuickTour>RelabelDoc (revision 3) (raw view)~~EditAttach~~

---+ Relabel

---++ Description

%ICON{wip}% TBA

This operation relabels the input and/or output labels of an FST. The relabeling can be specified by a set of pair of integer labels. 

When the FST has input and/or output symbol tables, the relabeling can be specified by giving new input and/or output symbol tables. The operation then modifies the interger labels of each arc in such a way that its symbolic labels are preserved.

---++ Usage

| <verbatim>
template <class Arc>
void Relabel(
    MutableFst<Arc> *fst,
    const vector<pair<typename Arc::Label, typename A::Label> >& ipairs,
    const vector<pair<typename Arc::Label, typename A::Label> >& opairs);
</verbatim> | %DOX{namespacefst.html#Relabel[%H%]}% |
| <verbatim>
template<class Arc>
void Relabel(
     MutableFst<Arc> *fst,
     const SymbolTable* new_isymbols,
     const SymbolTable* new_osymbols);
</verbatim> |^|
| <verbatim>
template <class Arc> RelabelFst<Arc>::
RelabelFst(const Fst<A>& fst,
             const vector<pair<Label, Label> >& ipairs,
             const vector<pair<Label, Label> >& opairs);
</verbatim> | %DOX{fst::RelabelFst[%H%]}% |
| <verbatim>
template <class Arc> RelabelFst<Arc>::
RelabelFst(const Fst<A>& fst,
             const SymbolTable* new_isymbols,
             const SymbolTable* new_osymbols)
</verbatim> |^|
| <verbatim>
fstrelabel [--relabel_ipairs=$ipairs] [--relabel_opairs=$opairs] in.fst out.fst 
</verbatim> ||
| <verbatim>
fstrelabel [--relabel_isymbols=$isyms] [--relabel_osymbols=$osyms] in.fst out.fst 
</verbatim> ||
---++ Examples

%ICON{wip}% TBA

---+++  =A=:

|   ==symbol table S1==   ||
| =eps= | =0= | 
| =a= | =1= |
| =b= | =2= |
| =c= | =3= |
| =d= | =4= |
| =f= | =5= |
| =g= | =6= |

|    ==A==   ||
| %ATTACHURL%/relabel.png | %ATTACHURL%/relabel_s1.png |

---+++ =B=:

|   ==S2==   ||
| eps | 0 | 
| g | 1 |
| f | 2 |
| d | 3 |
| c | 4 |
| b | 5 |
| a | 6 |

|    ==B==   ||
| %ATTACHURL%/relabel.png | %ATTACHURL%/relabel_s2.png |

<verbatim>

fstrelabel  --relabel_isymbols=s2 --relabel_osymbols=s2 a.fst b.fst
</verbatim>

---++ Complexity

=Relabel=
   * Time: _O(V + E + S<sub>i</sub> + S<sub>o</sub>)_
   * Space: _O(S<sub>i</sub> + S<sub>o</sub>)_
where _V_ = # of states, _E_ = # of arcs of the input FST, _S<sub>i</sub>_ = # of input symbols and _S<sub>o</sub>_ = # of output symbols. 

=RelabelFst=
   * Time: _O(v + e + S<sub>i</sub> + S<sub>o</sub>)_
   * Space: _O(S<sub>i</sub> + S<sub>o</sub>)_
where _v_ = # of states visited, _e_ = # of arcs visited of the input FST, _S<sub>i</sub>_ = # of input symbols and _S<sub>o</sub>_ = # of output symbols. Constant time and space to visit an input state or arc is assumed and exclusive of [[FstAdvancedUsage#FstCaching][caching]]. 

-- Main.CyrilAllauzen - 03 Mar 2009

Attachments

Topic attachments
I	Attachment	History	Action	Size	Date	Who	Comment
png	relabel.png	r1	manage	10.9 K	2009-03-25 - 22:38	CyrilAllauzen	Relabel example: fst `A`
png	relabel_s1.png	r3 r2 r1	manage	10.6 K	2009-03-25 - 23:27	CyrilAllauzen	Relabel example: fst `A` with integer labels
png	relabel_s2.png	r2 r1	manage	10.7 K	2009-03-25 - 23:27	CyrilAllauzen	Relabel example: fst `B` with integer labels

Topic revision: r3 - 2009-03-25 - CyrilAllauzen