/// <summary>
/// Gets the closest synset that is reachable from the current and another synset along the given relations. For example,
/// given two synsets and the Hypernym relation, this will return the lowest synset that is a hypernym of both synsets. If
/// the hypernym hierarchy forms a tree, this will be the lowest common ancestor.
/// </summary>
/// <param name="synset">Other synset</param>
/// <param name="relations">Relations to follow</param>
/// <returns>Closest mutually reachable synset</returns>
public SynSet GetClosestMutuallyReachableSynset(SynSet synset, IEnumerable<SynSetRelation> relations) {
var synSetRelations = relations as SynSetRelation[] ?? Enumerable.ToArray(relations);
var synsetsEncountered = new List<SynSet> { this };
var searchQueue = new Queue<SynSet>();
searchQueue.Enqueue(this);
// run search
SynSet closest = null;
while (searchQueue.Count > 0 && closest == null) {
var currSynSet = searchQueue.Dequeue();
/* check for a path between the given synset and the current one. if such a path exists, the current
* synset is the closest mutually reachable synset. */
if (synset.GetShortestPathTo(currSynSet, synSetRelations) != null)
closest = currSynSet;
// otherwise, expand the search along the given relations
else
foreach (var relatedSynset in currSynSet.GetRelatedSynSets(synSetRelations, false))
if (!synsetsEncountered.Contains(relatedSynset)) {
searchQueue.Enqueue(relatedSynset);
synsetsEncountered.Add(relatedSynset);
}
}
return closest;
}
/// <summary>
/// Gets the shortest path from the current synset to another, following the given synset relations.
/// </summary>
/// <param name="destination">Destination synset</param>
/// <param name="relations">Relations to follow, or null for all relations.</param>
/// <returns>Synset path, or null if none exists.</returns>
public List <SynSet> GetShortestPathTo(SynSet destination, IEnumerable <SynSetRelation> relations)
{
var synSetRelations = relations == null
? Enum.GetValues(typeof(SynSetRelation)) as SynSetRelation[]
: (relations as SynSetRelation[] ?? Enumerable.ToArray(relations));
// make sure the backpointer on the current synset is null - can't predict what other functions might do
SearchBackPointer = null;
// avoid cycles
var synsetsEncountered = new List <SynSet> {
this
};
// start search queue
var searchQueue = new Queue <SynSet>();
searchQueue.Enqueue(this);
// run search
List <SynSet> path = null;
while (searchQueue.Count > 0 && path == null)
{
var currSynSet = searchQueue.Dequeue();
// see if we've finished the search
if (currSynSet == destination)
{
// gather synsets along path
path = new List <SynSet>();
while (currSynSet != null)
{
path.Add(currSynSet);
currSynSet = currSynSet.SearchBackPointer;
}
// reverse for the correct order
path.Reverse();
}
// expand the search one level
else
{
foreach (var synset in currSynSet.GetRelatedSynSets(synSetRelations, false))
{
if (!synsetsEncountered.Contains(synset))
{
synset.SearchBackPointer = currSynSet;
searchQueue.Enqueue(synset);
synsetsEncountered.Add(synset);
}
}
}
}
// null-out all search backpointers
foreach (var synset in synsetsEncountered)
{
synset.SearchBackPointer = null;
}
return(path);
}
/// <summary>
/// Gets the shortest path from the current synset to another, following the given synset relations.
/// </summary>
/// <param name="destination">Destination synset</param>
/// <param name="relations">Relations to follow, or null for all relations.</param>
/// <returns>Synset path, or null if none exists.</returns>
public List<SynSet> GetShortestPathTo(SynSet destination, IEnumerable<SynSetRelation> relations) {
var synSetRelations = relations == null
? Enum.GetValues(typeof(SynSetRelation)) as SynSetRelation[]
: (relations as SynSetRelation[] ?? Enumerable.ToArray(relations));
// make sure the backpointer on the current synset is null - can't predict what other functions might do
SearchBackPointer = null;
// avoid cycles
var synsetsEncountered = new List<SynSet> { this };
// start search queue
var searchQueue = new Queue<SynSet>();
searchQueue.Enqueue(this);
// run search
List<SynSet> path = null;
while (searchQueue.Count > 0 && path == null) {
var currSynSet = searchQueue.Dequeue();
// see if we've finished the search
if (currSynSet == destination) {
// gather synsets along path
path = new List<SynSet>();
while (currSynSet != null) {
path.Add(currSynSet);
currSynSet = currSynSet.SearchBackPointer;
}
// reverse for the correct order
path.Reverse();
}
// expand the search one level
else {
foreach (var synset in currSynSet.GetRelatedSynSets(synSetRelations, false))
if (!synsetsEncountered.Contains(synset)) {
synset.SearchBackPointer = currSynSet;
searchQueue.Enqueue(synset);
synsetsEncountered.Add(synset);
}
}
}
// null-out all search backpointers
foreach (var synset in synsetsEncountered)
synset.SearchBackPointer = null;
return path;
}
