public Viterbi(int w, int h)
{
_w = w;
_h = h;
_decisionLattice = new decisionNode[w, h];
for (int i = 0; i < w; i++)
{
for (int j = 0; j < h; j++)
{
_decisionLattice[i, j] = new decisionNode();
}
}
for (int i = 0; i < w; i++)
{
double[] dAry = new double[h];
List <double> dList = new List <double>(dAry);
_nodeScore.Add(dList);
dMatrix m = new dMatrix(h, h);
_edgeScore.Add(m);
}
_edgeScore[0] = null;
}
//run viterbi from right to left, then get tags from left to right
//note: should not contain the value of current node into Heuristic,otherwise cur-val is added twice if it is also in "g"
public double runViterbi(ref List <int> states, bool exp)
{
for (int y = 0; y < _h; y++)
{
decisionNode curNode = _decisionLattice[_w - 1, y];
curNode._initCheck = true;
curNode._maxPreScore = 0;
curNode._maxNowScore = _nodeScore[_w - 1][y];
curNode._preY = -1;
}
for (int i = _w - 2; i >= 0; i--)
{
for (int y = 0; y < _h; y++)
{
for (int yPre = 0; yPre < _h; yPre++)
{
int iPre = i + 1;
//compute the new path-prob until now, compare it with the existing path-prob
//if the new one is bigger than current one, then update the path-prob and bkTrkNode
decisionNode preNode = _decisionLattice[iPre, yPre];
decisionNode curNode = _decisionLattice[i, y];
double score1 = _nodeScore[iPre][yPre];
double score2 = _edgeScore[iPre][y, yPre];
double score3 = preNode._maxPreScore;
double score4 = _nodeScore[i][y];
double preScore = score1 + score2 + score3;
if (!curNode._initCheck)
{
curNode._initCheck = true;
curNode._maxPreScore = preScore;
curNode._maxNowScore = preScore + score4;
curNode._preY = yPre;
}
else if (preScore >= curNode._maxPreScore)
{
curNode._maxPreScore = preScore;
curNode._maxNowScore = preScore + score4;
curNode._preY = yPre;
}
}
}
}
//get viterbi tags
states.Clear();
double max = _decisionLattice[0, 0]._maxNowScore;
int tag = 0;
for (int y = 1; y < _h; y++)
{
double sc = _decisionLattice[0, y]._maxNowScore;
if (max < sc)
{
max = sc;
tag = y;
}
}
states.Add(tag);
for (int i = 1; i < _w; i++)
{
int iPre = i - 1;
tag = _decisionLattice[iPre, tag]._preY;
states.Add(tag);
}
return(Math.Exp(max));
}
