private HashSet <NodeReference> getBackwardTargets(SemanticPart part, IEnumerable <NodeReference> endingNodes = null)
{
if (endingNodes == null)
{
endingNodes = new List <NodeReference>(new[] { part.StartNode });
}
var result = new HashSet <NodeReference>();
foreach (var path in part.Paths)
{
var currentLayer = endingNodes;
for (var i = path.Length - 1; i >= 0; --i)
{
var edge = path.GetEdge(i).Inverse();
var nextLayer = new List <NodeReference>();
foreach (var node in currentLayer)
{
var targets = Graph.Targets(node, edge);
nextLayer.AddRange(targets);
}
currentLayer = nextLayer;
}
result.UnionWith(currentLayer);
}
return(result);
}
private IEnumerable <SemanticPart> lastRelevantUtterances(string question, NodeReference answer)
{
var result = new List <SemanticPart>();
foreach (var word in UtteranceParser.Parse(question).Words)
{
var fromNode = Graph.GetNode(word);
var paths = Graph.GetPaths(fromNode, answer, MaximumGraphDepth, MaximumGraphWidth).Take(1).ToArray();
if (paths.Length == 0)
{
//there is no evidence
continue;
}
var part = new SemanticPart(question, paths);
result.Add(part);
}
return(result);
}
