/**
* /// Expands the given hmm state tree
*
* /// @param parent the parent of the tree
* /// @param tree the tree to expand
* /// @return the final state in the tree
*/
private HMMStateState ExpandHMMTree(UnitState parent, HMMStateState tree)
{
HMMStateState retState = tree;
foreach (HmmStateArc arc in tree.HmmState.GetSuccessors())
{
HMMStateState newState;
if (arc.HmmState.IsEmitting)
{
newState = new HMMStateState(parent, arc.HmmState);
}
else
{
newState = new NonEmittingHMMState(parent, arc.HmmState);
}
SentenceHMMState existingState = GetExistingState(newState);
float logProb = arc.LogProbability;
if (existingState != null)
{
AttachState(tree, existingState, LogOne, logProb);
}
else
{
AttachState(tree, newState, LogOne, logProb);
AddStateToCache(newState);
retState = ExpandHMMTree(parent, newState);
}
}
return(retState);
}
/**
* /// Expands the given hmm state tree
*
* /// @param parent the parent of the tree
* /// @param tree the tree to expand
* /// @return the final state in the tree
*/
protected HMMStateState ExpandHMMTree(UnitState parent, HMMStateState tree)
{
var retState = tree;
foreach (var arc in tree.HmmState.GetSuccessors())
{
HMMStateState newState;
if (arc.HmmState.IsEmitting)
{
newState = new HMMStateState(parent, arc.HmmState);
}
else
{
newState = new NonEmittingHMMState(parent, arc.HmmState);
}
var existingState = GetExistingState(newState);
var logProb = arc.LogProbability;
if (existingState != null)
{
AttachState(tree, existingState, _parent.LogOne, logProb);
}
else
{
AttachState(tree, newState, _parent.LogOne, logProb);
AddStateToCache(newState);
retState = ExpandHMMTree(parent, newState);
}
}
return(retState);
}
/**
* /// Given a unit state, return the set of sentence hmm states associated with the unit
*
* /// @param unitState the unit state of intereset
* /// @return the hmm tree for the unit
*/
private HMMStateState GetHMMStates(UnitState unitState)
{
HMMStateState hmmTree;
HMMStateState finalState;
Unit unit = unitState.Unit;
HMMPosition position = unitState.GetPosition();
IHMM hmm = _parent._acousticModel.LookupNearestHMM(unit, position, false);
IHMMState initialState = hmm.GetInitialState();
hmmTree = new HMMStateState(unitState, initialState);
AttachState(unitState, hmmTree, LogOne, LogOne);
AddStateToCache(hmmTree);
finalState = ExpandHMMTree(unitState, hmmTree);
return(finalState);
}
/** Constructs a phone loop search graph. */
public PhoneLoopSearchGraph(CIPhoneLoop parent)
{
_parent = parent;
ExistingStates = new Dictionary <string, ISearchState>();
FirstState = new UnknownWordState();
SentenceHMMState branchState = new BranchOutState(FirstState);
AttachState(FirstState, branchState, _parent.LogOne, _parent.LogOne);
SentenceHMMState lastState = new LoopBackState(FirstState);
lastState.SetFinalState(true);
AttachState(lastState, branchState, _parent.LogOne, _parent.LogOne);
for (var i = _parent.Model.GetContextIndependentUnitIterator(); i.MoveNext();)
{
var unitState = new UnitState(i.Current, HMMPosition.Undefined);
var debug = unitState.ToString();
// attach unit state to the branch out state
AttachState(branchState, unitState, _parent.LogOne, _parent.LogPhoneInsertionProbability);
var hmm = _parent.Model.LookupNearestHMM(unitState.Unit, unitState.GetPosition(), false);
var initialState = hmm.GetInitialState();
var hmmTree = new HMMStateState(unitState, initialState);
AddStateToCache(hmmTree);
// attach first HMM state to the unit state
AttachState(unitState, hmmTree, _parent.LogOne, _parent.LogOne);
// expand the HMM tree
var finalState = ExpandHMMTree(unitState, hmmTree);
// attach final state of HMM tree to the loopback state
AttachState(finalState, lastState, _parent.LogOne, _parent.LogOne);
}
}
