// TODO: I really hate this pattern. Find a way to accomplish this without
// either using obnoxious patterns or opening the door for confusing usage.
public bool TryRecognizeTrajectory(Trajectory trajectory, out string result)
{
var descriptor = new TrajectoryDescriptor(trajectory, this.vectorsAlphabet, this.levenshteinAlphabet);
result = null;
var allowableMatches = this.knownStrings.Where(pair => pair.Value.GetMatchCost(descriptor) < MAXIMUM_ALLOWABLE_MATCH_COST);
if (allowableMatches.Count() == 0)
{
return(false);
}
else
{
float bestDistance = float.MaxValue;
foreach (var pair in allowableMatches)
{
float distance = pair.Value.GetMatchMinimumEditDistance(descriptor);
if (distance < bestDistance)
{
result = pair.Key;
bestDistance = distance;
}
}
return(result != null);
}
}
public float Distance(TrajectoryDescriptor other)
{
Debug.Assert(this.Strings.Count == other.Strings.Count);
float totalDistance = 0;
for (int idx = 0; idx < this.Strings.Count; idx++)
{
float weight = Mathf.Pow(2f, idx);
totalDistance += this.Strings[idx].Distance(other.Strings[idx]);
}
return(totalDistance);
}
// TODO: Try best match score? Sum of squared distances?
public float GetMatchCost(TrajectoryDescriptor descriptor)
{
float cost = descriptor.Distance(this.Descriptors[this.centroidIdx]);
return(cost / this.averageLevenshteinDistance); // Linear error metric, for now.
}
public float GetMatchMinimumEditDistance(TrajectoryDescriptor descriptor)
{
return(this.Descriptors.Min(desc => desc.Distance(descriptor)));
}
public void Add(TrajectoryDescriptor descriptor)
{
this.Descriptors.Add(descriptor);
this.RecalculateRepresentations(this.Descriptors);
}
