/**
* Makes a CSP consisting of binary constraints arc-consistent.
*
* @return An object which indicates success/failure and contains data to
* undo the operation.
*/
public IInferenceLog <VAR, VAL> apply(CSP <VAR, VAL> csp)
{
ICollection <VAR> queue = CollectionFactory.CreateFifoQueueNoDuplicates <VAR>();
queue.AddAll(csp.getVariables());
DomainLog <VAR, VAL> log = new DomainLog <VAR, VAL>();
reduceDomains(queue, csp, log);
return(log.compactify());
}
// END-BayesianNetwork
//
//
// PRIVATE METHODS
//
private void checkIsDAGAndCollectVariablesInTopologicalOrder()
{
// Topological sort based on logic described at:
// http://en.wikipedia.org/wiki/Topoligical_sorting
ISet <INode> seenAlready = CollectionFactory.CreateSet <INode>();
IMap <INode, ICollection <INode> > incomingEdges = CollectionFactory.CreateMap <INode, ICollection <INode> >();
ICollection <INode> s = CollectionFactory.CreateFifoQueueNoDuplicates <INode>();
foreach (INode n in this.rootNodes)
{
walkNode(n, seenAlready, incomingEdges, s);
}
while (!s.IsEmpty())
{
INode n = s.Pop();
variables.Add(n.GetRandomVariable());
varToNodeMap.Put(n.GetRandomVariable(), n);
foreach (INode m in n.GetChildren())
{
ICollection <INode> edges = incomingEdges.Get(m);
edges.Remove(n);
if (edges.IsEmpty())
{
s.Add(m);
}
}
}
foreach (ICollection <INode> edges in incomingEdges.GetValues())
{
if (!edges.IsEmpty())
{
throw new IllegalArgumentException("Network contains at least one cycle in it, must be a DAG.");
}
}
}
