/// <summary>
/// Determine whether node is contained in currrent or previous segments.
/// </summary>
/// <param name="node">Tested node.</param>
/// <returns><c>true</c> whether node is contained, <c>false</c> otherwise.</returns>
internal bool Contains(NodeReference node)
{
if (Node.Equals(node))
{
return(true);
}
if (PreviousSegment == null)
{
return(false);
}
return(PreviousSegment.Contains(node));
}
/// <summary>
/// Get paths between given nodes.
/// </summary>
/// <param name="from"></param>
/// <param name="to"></param>
/// <param name="maxLength"></param>
/// <param name="maxWidth"></param>
/// <returns></returns>
public IEnumerable <KnowledgePath> GetPaths(NodeReference from, NodeReference to, int maxLength, int maxWidth)
{
if (from == null || to == null)
{
yield break;
}
var currentQueue = new Queue <PathSegment>();
var visitedNodes = new HashSet <NodeReference>();
var startSegment = new PathSegment(null, null, from);
if (from.Equals(to))
{
yield return(new KnowledgePath(startSegment));
yield break;
}
//starting node
currentQueue.Enqueue(startSegment);
//delimiter - for counting path length
currentQueue.Enqueue(null);
visitedNodes.Add(from);
visitedNodes.Add(to);
var currentPathLength = 0;
while (currentQueue.Count > 0 && currentPathLength < maxLength)
{
var currentSegment = currentQueue.Dequeue();
if (currentSegment == null)
{
++currentPathLength;
//add next delimiter
currentQueue.Enqueue(null);
continue;
}
//test if we can get into end node
foreach (var edge in BetweenEdges(currentSegment.Node, to))
{
var segment = new PathSegment(currentSegment, edge, to);
yield return(new KnowledgePath(segment));
}
//explore next children
foreach (var childPair in GetNeighbours(currentSegment.Node, maxWidth))
{
var edge = childPair.Item1;
var child = childPair.Item2;
if (!visitedNodes.Add(child))
{
//this node has already been visited
continue;
}
var childSegment = new PathSegment(currentSegment, edge, child);
currentQueue.Enqueue(childSegment);
}
}
}