/// <summary>
/// <see cref="object.Equals(object)"/>
/// </summary>
public override bool Equals(object obj)
{
if (this == obj)
{
return(true);
}
if (obj == null)
{
return(false);
}
if (GetType() != obj.GetType())
{
return(false);
}
SegTokenPair other = (SegTokenPair)obj;
if (!Arrays.Equals(CharArray, other.CharArray))
{
return(false);
}
if (From != other.From)
{
return(false);
}
if (To != other.To)
{
return(false);
}
if (Number.DoubleToInt64Bits(Weight) != Number
.DoubleToInt64Bits(other.Weight))
{
return(false);
}
return(true);
}
public virtual IList <SegToken> GetShortPath()
{
int current;
int nodeCount = ToCount;
IList <PathNode> path = new List <PathNode>();
PathNode zeroPath = new PathNode();
zeroPath.Weight = 0;
zeroPath.PreNode = 0;
path.Add(zeroPath);
for (current = 1; current <= nodeCount; current++)
{
double weight;
IList <SegTokenPair> edges = GetToList(current);
double minWeight = double.MaxValue;
SegTokenPair minEdge = null;
foreach (SegTokenPair edge in edges)
{
weight = edge.Weight;
PathNode preNode2 = path[edge.From];
if (preNode2.Weight + weight < minWeight)
{
minWeight = preNode2.Weight + weight;
minEdge = edge;
}
}
PathNode newNode = new PathNode();
newNode.Weight = minWeight;
newNode.PreNode = minEdge.From;
path.Add(newNode);
}
// Calculate PathNodes
int preNode, lastNode;
lastNode = path.Count - 1;
current = lastNode;
IList <int> rpath = new List <int>();
IList <SegToken> resultPath = new List <SegToken>();
rpath.Add(current);
while (current != 0)
{
PathNode currentPathNode = path[current];
preNode = currentPathNode.PreNode;
rpath.Add(preNode);
current = preNode;
}
for (int j = rpath.Count - 1; j >= 0; j--)
{
//int idInteger = rpath.get(j);
//int id = idInteger.intValue();
int id = rpath[j];
SegToken t = segTokenList[id];
resultPath.Add(t);
}
return(resultPath);
}
/// <summary>
/// Add a <see cref="SegTokenPair"/>
/// </summary>
/// <param name="tokenPair"><see cref="SegTokenPair"/></param>
public virtual void AddSegTokenPair(SegTokenPair tokenPair)
{
int to = tokenPair.To;
if (!IsToExist(to))
{
List <SegTokenPair> newlist = new List <SegTokenPair>();
newlist.Add(tokenPair);
tokenPairListTable[to] = newlist;
}
else
{
IList <SegTokenPair> tokenPairList = tokenPairListTable[to];
tokenPairList.Add(tokenPair);
}
}
/// <summary>
/// Generate a <see cref="BiSegGraph"/> based upon a <see cref="SegGraph"/>
/// </summary>
private void GenerateBiSegGraph(SegGraph segGraph)
{
double smooth = 0.1;
int wordPairFreq = 0;
int maxStart = segGraph.MaxStart;
double oneWordFreq, weight, tinyDouble = 1.0 / Utility.MAX_FREQUENCE;
int next;
char[] idBuffer;
// get the list of tokens ordered and indexed
segTokenList = segGraph.MakeIndex();
// Because the beginning position of startToken is -1, therefore startToken can be obtained when key = -1
int key = -1;
IList <SegToken> nextTokens = null;
while (key < maxStart)
{
if (segGraph.IsStartExist(key))
{
IList <SegToken> tokenList = segGraph.GetStartList(key);
// Calculate all tokens for a given key.
foreach (SegToken t1 in tokenList)
{
oneWordFreq = t1.Weight;
next = t1.EndOffset;
nextTokens = null;
// Find the next corresponding Token.
// For example: "Sunny seashore", the present Token is "sunny", next one should be "sea" or "seashore".
// If we cannot find the next Token, then go to the end and repeat the same cycle.
while (next <= maxStart)
{
// Because the beginning position of endToken is sentenceLen, so equal to sentenceLen can find endToken.
if (segGraph.IsStartExist(next))
{
nextTokens = segGraph.GetStartList(next);
break;
}
next++;
}
if (nextTokens == null)
{
break;
}
foreach (SegToken t2 in nextTokens)
{
idBuffer = new char[t1.CharArray.Length + t2.CharArray.Length + 1];
System.Array.Copy(t1.CharArray, 0, idBuffer, 0, t1.CharArray.Length);
idBuffer[t1.CharArray.Length] = BigramDictionary.WORD_SEGMENT_CHAR;
System.Array.Copy(t2.CharArray, 0, idBuffer,
t1.CharArray.Length + 1, t2.CharArray.Length);
// Two linked Words frequency
wordPairFreq = bigramDict.GetFrequency(idBuffer);
// Smoothing
// -log{a*P(Ci-1)+(1-a)P(Ci|Ci-1)} Note 0<a<1
weight = -Math
.Log(smooth
* (1.0 + oneWordFreq)
/ (Utility.MAX_FREQUENCE + 0.0)
+ (1.0 - smooth)
* ((1.0 - tinyDouble) * wordPairFreq / (1.0 + oneWordFreq) + tinyDouble));
SegTokenPair tokenPair = new SegTokenPair(idBuffer, t1.Index,
t2.Index, weight);
this.AddSegTokenPair(tokenPair);
}
}
}
key++;
}
}
