public void UpdateCurrentPos()
{
_oldPos = _currentPos;
_currentPos = _lastPath[_lastPath.Count - 1];
Bounds = new HmmWindow(_windowSize, _currentPos, Data.InitialLogs.Length);
}
public void Reset()
{
_observations = new List <int>();
_lastObservations = new List <int>();
_path = new List <int>();
_oldPos = -1;
_currentPos = -1;
Bounds = new HmmWindow(_windowSize, 0, Data.InitialLogs.Length);
}
private double[,] ForwardWindow(out double[] c)
{
int statesCount = _windowSize;
int observsCount = _lastObservations.Count;
double[,] fwd = new double[observsCount, statesCount];
c = new double[observsCount];
HmmWindow window = new HmmWindow(_windowSize, _currentPos, Data.InitialLogs.Length);
// 1. Initialization
for (int i = window.LeftBound; i < window.RightBound; i++)
{
fwd[0, i - window.LeftBound] = Data.InitialLogs[i] * Data.EmissionsLogs[i, _lastObservations[0]];
c[0] += fwd[0, i - window.LeftBound];
}
if (c[0] != 0)
{
for (int i = 0; i < statesCount; i++)
{
fwd[0, i] = fwd[0, i] / c[0];
}
}
// 2. Induction
for (int t = 1; t < observsCount; t++)
{
for (int i = window.LeftBound; i < window.RightBound; i++)
{
double p = Data.EmissionsLogs[i, _lastObservations[t]];
double sum = 0.0;
for (int j = window.LeftBound; j < window.RightBound; j++)
{
sum += fwd[t - 1, j - window.LeftBound] * Data.TransitionsLogs[j, i];
}
fwd[t, i - window.LeftBound] = sum * p;
c[t] += fwd[t, i - window.LeftBound]; // scaling coefficient
}
if (c[t] != 0) // Scaling
{
for (int i = 0; i < statesCount; i++)
{
fwd[t, i] = fwd[t, i] / c[t];
}
}
}
return(fwd);
}
private double[,] BackwardWindow(double[] c)
{
int statesCount = _windowSize;
int observsCount = _lastObservations.Count;
double[,] bwd = new double[observsCount, statesCount];
HmmWindow window = new HmmWindow(_windowSize, _currentPos, Data.InitialLogs.Length);
for (int i = window.LeftBound; i < window.RightBound; i++)
{
bwd[0, i - window.LeftBound] = Data.InitialLogs[i] * Data.EmissionsLogs[i, _lastObservations[0]];
}
// 1. Initialization
if (c[0] != 0)
{
for (int i = 0; i < statesCount; i++)
{
bwd[0, i] = bwd[0, i] / c[0];
}
}
// 2. Induction
for (int t = observsCount - 2; t >= 0; t--)
{
for (int i = window.LeftBound; i < window.RightBound; i++)
{
double sum = 0.0;
for (int j = window.LeftBound; j < window.RightBound; j++)
{
sum += bwd[t + 1, j - window.LeftBound] * Data.TransitionsLogs[i, j] * Data.EmissionsLogs[j, _lastObservations[t + 1]];
}
bwd[t, i - window.LeftBound] += sum;
}
if (c[t] != 0) // Scaling
{
for (int i = 0; i < statesCount; i++)
{
bwd[t, i] = bwd[t, i] / c[t];
}
}
}
return(bwd);
}
