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);
}
public static void Main(string[] args)
{
/*
* TransducerGraph fa = new TransducerGraph();
* fa.addArc(fa.getStartNode(),"1","a","");
* fa.addArc(fa.getStartNode(),"2","b","");
* fa.addArc(fa.getStartNode(),"3","c","");
* fa.addArc("1","4","a","");
* fa.addArc("2","4","a","");
* fa.addArc("3","5","c","");
* fa.addArc("4",fa.getEndNode(),"c","");
* fa.addArc("5",fa.getEndNode(),"c","");
* System.out.println(fa);
* ExactAutomatonMinimizer minimizer = new ExactAutomatonMinimizer();
* System.out.println(minimizer.minimizeFA(fa));
*/
System.Console.Out.WriteLine("Starting minimizer test...");
IList pathList = new ArrayList();
TransducerGraph randomFA = TransducerGraph.CreateRandomGraph(5000, 5, 1.0, 5, pathList);
IList outputs = randomFA.GetPathOutputs(pathList);
TransducerGraph.IGraphProcessor quasiDeterminizer = new QuasiDeterminizer();
IAutomatonMinimizer minimizer = new FastExactAutomatonMinimizer();
TransducerGraph.INodeProcessor ntsp = new TransducerGraph.SetToStringNodeProcessor(new PennTreebankLanguagePack());
TransducerGraph.IArcProcessor isp = new TransducerGraph.InputSplittingProcessor();
TransducerGraph.IArcProcessor ocp = new TransducerGraph.OutputCombiningProcessor();
TransducerGraph detGraph = quasiDeterminizer.ProcessGraph(randomFA);
TransducerGraph combGraph = new TransducerGraph(detGraph, ocp);
// combine outputs into inputs
TransducerGraph result = minimizer.MinimizeFA(combGraph);
// minimize the thing
System.Console.Out.WriteLine("Minimized from " + randomFA.GetNodes().Count + " to " + result.GetNodes().Count);
result = new TransducerGraph(result, ntsp);
// pull out strings from sets returned by minimizer
result = new TransducerGraph(result, isp);
// split outputs from inputs
IList minOutputs = result.GetPathOutputs(pathList);
System.Console.Out.WriteLine("Equal? " + outputs.Equals(minOutputs));
}
/// <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);
}
