public double CalculatePriorPrabability(PointAttributeGroup attributes, bool value)
{
//P(EOS) | P(notEOS)
return(_data.FirstOrDefault(t => t.Type == value)
.TotalCount + (IsSmoothed ? LaplacianSmoothing : 0.0)
/ _data.Sum(x => x.TotalCount) + (IsSmoothed ? LaplacianSmoothingV : 0.0));
}
public double CalculateLikelihood(PointAttributeGroup attributes, bool value)
{
//P(PreviousNext|EOS) P(PreviousNext|notEOS)
return((_data.FirstOrDefault(t => t.Type == value).Attributes
.FirstOrDefault(r => r.Group.Previous == attributes.Previous && r.Group.Next == attributes.Next)?.Count ?? 0.0) + (IsSmoothed ? LaplacianSmoothing : 0.0)
/ _data.FirstOrDefault(t => t.Type == value).TotalCount + (IsSmoothed ? LaplacianSmoothingV : 0.0));
}
public double CalculateEvidence(PointAttributeGroup attributes)
{
//P(PreviousNext)
return(_data.SelectMany(x => x.Attributes)
.Where(r => r.Group.Previous == attributes.Previous && r.Group.Next == attributes.Next)
.Sum(c => c.Count) + (IsSmoothed ? LaplacianSmoothing : 0.0)
/ _data.Sum(x => x.TotalCount) + (IsSmoothed ? LaplacianSmoothingV : 0.0));
}
public PointFeature(RegisterGroup previous, RegisterGroup next, bool isEOS)
{
Feature = new PointAttributeGroup()
{
Previous = previous,
Next = next
};
IsEOS = isEOS;
}
public bool Classify(PointAttributeGroup attributes, EOSOptions option)
{
IsSmoothed = option == EOSOptions.LaplacianSmoothing ? true : false;
double evidence = CalculateEvidence(attributes);
double eosPP = CalculatePriorPrabability(attributes, true);
double notEosPP = CalculatePriorPrabability(attributes, false);
double eosLikelihood = CalculateLikelihood(attributes, true);
double notEosLikelihood = CalculateLikelihood(attributes, false);
//P(EOS|PreviousNext) = P(PreviousNext|EOS) * P(EOS) / P(PreviousNext)
double eos = (eosLikelihood * eosPP) / evidence;
//P(notEOS|PreviousNext) = P(PreviousNext|notEOS) * P(notEOS) / P(PreviousNext)
double notEos = (notEosLikelihood * notEosPP) / evidence;
if (eos > notEos)
{
return(true);
}
return(false);
}