public virtual TransducerGraph ProcessGraph(TransducerGraph g)
{
g = new TransducerGraph(g);
ISet nodes = g.GetNodes();
foreach (object node in nodes)
{
ICollection <TransducerGraph.Arc> myArcs = null;
if (forward)
{
myArcs = g.GetArcsBySource(node);
}
else
{
myArcs = g.GetArcsByTarget(node);
}
// compute a total
double total = 0.0;
foreach (TransducerGraph.Arc a in myArcs)
{
total += ((double)a.GetOutput());
}
// divide each by total
foreach (TransducerGraph.Arc a_1 in myArcs)
{
a_1.SetOutput(Math.Log(((double)a_1.GetOutput()) / total));
}
}
return(g);
}
/// <summary>Takes time linear in number of arcs.</summary>
public virtual TransducerGraph PushLambdas(TransducerGraph graph, ClassicCounter lambda)
{
TransducerGraph result = null;
result = graph.Clone();
// arcs have been copied too so we don't mess up graph
ICollection <TransducerGraph.Arc> arcs = result.GetArcs();
foreach (TransducerGraph.Arc arc in arcs)
{
double sourceLambda = lambda.GetCount(arc.GetSourceNode());
double targetLambda = lambda.GetCount(arc.GetTargetNode());
double oldOutput = ((double)arc.GetOutput());
double newOutput = oldOutput + targetLambda - sourceLambda;
arc.SetOutput(newOutput);
}
// do initialOutput
double startLambda = lambda.GetCount(result.GetStartNode());
if (startLambda != 0.0)
{
// add it back to the outbound arcs from start (instead of adding it to the initialOutput)
ICollection <TransducerGraph.Arc> startArcs = result.GetArcsBySource(result.GetStartNode());
foreach (TransducerGraph.Arc arc_1 in startArcs)
{
double oldOutput = ((double)arc_1.GetOutput());
double newOutput = oldOutput + startLambda;
arc_1.SetOutput(newOutput);
}
}
// do finalOutput
foreach (object o in result.GetEndNodes())
{
double endLambda = lambda.GetCount(o);
if (endLambda != 0.0)
{
// subtract it from the inbound arcs to end (instead of subtracting it from the finalOutput)
ICollection <TransducerGraph.Arc> endArcs = result.GetArcsByTarget(o);
foreach (TransducerGraph.Arc arc_1 in endArcs)
{
double oldOutput = ((double)arc_1.GetOutput());
double newOutput = oldOutput - endLambda;
arc_1.SetOutput(newOutput);
}
}
}
return(result);
}
/// <summary>Takes time linear in number of arcs.</summary>
public static ClassicCounter ComputeLambda(TransducerGraph graph)
{
ArrayList queue = new ArrayList();
ClassicCounter lambda = new ClassicCounter();
ClassicCounter length = new ClassicCounter();
IDictionary first = new Hashtable();
ISet nodes = graph.GetNodes();
foreach (object node in nodes)
{
lambda.SetCount(node, 0);
length.SetCount(node, double.PositiveInfinity);
}
ISet endNodes = graph.GetEndNodes();
foreach (object o in endNodes)
{
lambda.SetCount(o, 0);
length.SetCount(o, 0);
queue.AddLast(o);
}
// Breadth first search
// get the first node from the queue
object node_1 = null;
try
{
node_1 = queue.RemoveFirst();
}
catch (NoSuchElementException)
{
}
while (node_1 != null)
{
double oldLen = length.GetCount(node_1);
ISet arcs = graph.GetArcsByTarget(node_1);
if (arcs != null)
{
foreach (object arc1 in arcs)
{
TransducerGraph.Arc arc = (TransducerGraph.Arc)arc1;
object newNode = arc.GetSourceNode();
IComparable a = (IComparable)arc.GetInput();
double k = ((double)arc.GetOutput());
double newLen = length.GetCount(newNode);
if (newLen == double.PositiveInfinity)
{
// we are discovering this
queue.AddLast(newNode);
}
IComparable f = (IComparable)first[newNode];
if (newLen == double.PositiveInfinity || (newLen == oldLen + 1 && a.CompareTo(f) < 0))
{
// f can't be null, since we have a newLen
// we do this to this to newNode when we have new info, possibly many times
first[newNode] = a;
// ejecting old one if necessary
length.SetCount(newNode, oldLen + 1);
// this may already be the case
lambda.SetCount(newNode, k + lambda.GetCount(node_1));
}
}
}
// get a new node from the queue
node_1 = null;
try
{
node_1 = queue.RemoveFirst();
}
catch (NoSuchElementException)
{
}
}
return(lambda);
}