private Tuple <int[, ], int> ViterbiCore(string sentence)
{
int len = sentence.Length;
var weight = new double[len, 4];
var path = new int[len, 4];
for (int i = 0; i < len; i++)
{
if (i == 0)
{
for (int j = 0; j < 4; j++)
{
weight[i, j] = HiddenMarkovModel.GetInitProb(j, sentence[i]);
}
continue;
}
for (int j = 0; j < 4; j++)
{
weight[i, j] = Helper.MinValue;
path[i, j] = -1;
for (int k = 0; k < 4; k++)
{
double tmp = weight[i - 1, k] + HiddenMarkovModel.GetNextProb(k, j, sentence[i]);
if (tmp > weight[i, j])
{
weight[i, j] = tmp;
path[i, j] = k;
}
}
}
}
return(new Tuple <int[, ], int>(path, weight[len - 1, 1] >= weight[len - 1, 3] ? 1 : 3));
}
