///**
///// Create a decoder by loading the serialized model from a specified
///// filename
/////
///// @param g2pmodel_file
///// the filename of the serialized model
// */
//public G2PConverter(String g2pmodel_file)
//{
// g2pmodel = ImmutableFst.loadModel(g2pmodel_file);
// init();
//}
/**
* /// Initialize the decoder
*/
private void Init()
{
_skipSeqs.Add(Eps);
_skipSeqs.Add(Sb);
_skipSeqs.Add(Se);
_skipSeqs.Add(Skip);
_skipSeqs.Add("-");
// keep an augmented copy (for compose)
Compose.Augment(0, _g2Pmodel, _g2Pmodel.Semiring);
ArcSort.Apply(_g2Pmodel, new ILabelCompare());
var isyms = _g2Pmodel.Isyms;
LoadClusters(isyms);
// get epsilon filter for composition
_epsilonFilter = Compose.GetFilter(_g2Pmodel.Isyms, _g2Pmodel.Semiring);
ArcSort.Apply(_epsilonFilter, new ILabelCompare());
}
/**
* /// Finds nbest paths in an Fst returned by NShortestPaths operation
* ///
* /// @param fst
* /// the input fst
* /// @param nbest
* /// the number of paths to return
* /// @param skipSeqs
* /// the sequences to ignore
* /// @param tie
* /// the separator symbol
* /// @return the paths
*/
private List <Path> FindAllPaths(Fsts.Fst fst, int nbest, HashSet <String> skipSeqs, string tie)
{
var semiring = fst.Semiring;
// ArrayList<Path> finalPaths = new ArrayList<Path>();
var finalPaths = new Dictionary <String, Path>();
var paths = new Dictionary <State, Path>();
var queue = new Queue <State>();
var p = new Path(fst.Semiring);
p.Cost = semiring.One;
paths.Add(fst.Start, p);
queue.Enqueue(fst.Start);
var osyms = fst.Osyms;
while (queue.Count != 0)
{
var s = queue.Dequeue();
var currentPath = paths[s];
if (s.FinalWeight != semiring.Zero)
{
var pathString = currentPath.GetPath().ToString();
if (finalPaths.ContainsKey(pathString))
{
// path already exist. update its cost
var old = finalPaths[pathString];
if (old.Cost > currentPath.Cost)
{
finalPaths.Add(pathString, currentPath);
}
}
else
{
finalPaths.Add(pathString, currentPath);
}
}
var numArcs = s.GetNumArcs();
for (var j = 0; j < numArcs; j++)
{
var a = s.GetArc(j);
p = new Path(fst.Semiring);
var cur = paths[s];
p.Cost = cur.Cost;
p.SetPath(cur.GetPath().ToList());
var sym = osyms[a.Olabel];
var symsArray = sym.Split(new String[] { "\\" + tie }, StringSplitOptions.None);
for (var i = 0; i < symsArray.Length; i++)
{
var phone = symsArray[i];
if (!skipSeqs.Contains(phone))
{
p.GetPath().Add(phone);
}
}
p.Cost = semiring.Times(p.Cost, a.Weight);
var nextState = a.NextState;
paths.Add(nextState, p);
if (!queue.Contains(nextState))
{
queue.Enqueue(nextState);
}
}
}
var res = new List <Path>();
foreach (var path in finalPaths.Values)
{
res.Add(path);
}
res.Sort(new PathComparator());
var numPaths = res.Count;
for (var i = nbest; i < numPaths; i++)
{
res.RemoveAt(res.Count - 1);
}
return(res);
}
/**
* /// Transforms an input spelling/pronunciation into an equivalent FSA, adding
* /// extra arcs as needed to accommodate clusters.
* ///
* /// @param entry
* /// the input vector
* /// @return the created fst
*/
private Fsts.Fst EntryToFsa(List <String> entry)
{
var ts = new TropicalSemiring();
var efst = new Fsts.Fst(ts);
var s = new State(ts.Zero);
efst.AddState(s);
efst.SetStart(s);
// Build the basic FSA
for (var i = 0; i < entry.Count + 1; i++)
{
s = new State(ts.Zero);
efst.AddState(s);
if (i >= 1)
{
var symIndex = Utils.GetIndex(_g2Pmodel.Isyms,
entry[i - 1]);
efst.GetState(i).AddArc(new Arc(symIndex, symIndex, 0.0f, s));
}
else if (i == 0)
{
var symIndex = Utils.GetIndex(_g2Pmodel.Isyms, Sb);
efst.Start.AddArc(new Arc(symIndex, symIndex, 0.0f, s));
}
if (i == entry.Count)
{
var s1 = new State(ts.Zero);
efst.AddState(s1);
var symIndex = Utils.GetIndex(_g2Pmodel.Isyms, Se);
s.AddArc(new Arc(symIndex, symIndex, 0.0f, s1));
s1.FinalWeight = 0.0f;
}
}
// Add any cluster arcs
for (var value = 0; value < _clusters.Count; value++)
{
var cluster = _clusters[value];
if (cluster != null)
{
var start = 0;
var k = 0;
while (k != -1)
{
k = Utils.Search(entry, cluster, start);
if (k != -1)
{
var from = efst.GetState(start + k + 1);
from.AddArc(new Arc(value, value, 0.0f, efst
.GetState(start + k + cluster.Count + 1)));
start = start + k + cluster.Count;
}
}
}
}
efst.Isyms = _g2Pmodel.Isyms;
efst.Osyms = _g2Pmodel.Isyms;
return(efst);
}
