public double evaluate(IEnumerable <Observation> O, bool endStateOnly = false)
{
var currentProxels = new ProxelSet();
//create initialProxel
for (int i = 0; i < startStates.Length; i++)
{
currentProxels.Add(new Proxel(startStates[i], startStates[i].InitialProbability));
}
long prevTime = O.First().Time;
foreach (var o in O.Skip(1))
{
if (currentProxels.Count <= 0)
{
break;
}
currentProxels = forwardStep(currentProxels, (int)(o.Time - prevTime), o.Symbol);
prevTime = o.Time;
}
var sum = 0d;
if (endStateOnly)
{
var endProxels = currentProxels.Where(p => p.State == EndState);
foreach (Proxel p in endProxels)
{
sum += p.P;
}
}
else
{
foreach (Proxel p in currentProxels)
{
sum += p.P;
}
}
return(sum);
}
private ProxelSet forwardStep(ProxelSet proxels, int dT, string symbol)
{
ProxelSet newProxels = new ProxelSet();
foreach (Proxel p in proxels)
{
var transitions = ((State)p.State).Transitions;
if (transitions == null || transitions.Count < 1)
{
continue;
}
double P = 1; //Psojourn
foreach (Transition t in transitions)
{
P *= 1 - t.Dist.getCDF(dT);
}
if (P == 0)
{
continue;
}
//create childproxel for every active transition
double b;
foreach (Transition t in transitions)
{
if (t.OutputProbs.TryGetValue(symbol, out b))
{
double z = t.Dist.getHRF(dT);
if (z > 0)
{
newProxels.Add(new Proxel(t.PostState, p.P * P * z * b));
}
}
}
}
return(newProxels);
}