/// <summary>
/// Adds a point to a streaming cloud : the mean and variance of the clouds are updated.
/// </summary>
/// <param name="point">The point to add to the cloud.</param>
public void Add(WeightedPoint point)
{
_nbPoints++;
if (_barycenter == null)
{
_barycenter = new WeightedPoint(point.X, point.Y, 1);
_dispersion = 0;
}
else
{
_barycenter = _barycenter.Multiply(_nbPoints - 1);
_barycenter = _barycenter.Add(point);
_barycenter = _barycenter.Divide(_nbPoints);
_dispersion = (_dispersion * (_nbPoints - 1) + Distances.Euclide(_barycenter, point)) / _nbPoints;
}
}
/// <summary>
/// Given a list of WeightedPoints returns.
/// </summary>
/// <param name="weightedPoints">Weighted points to average.</param>
/// <returns>The barycenter of the input points.</returns>
public static WeightedPoint Barycenter(IList<WeightedPoint> weightedPoints)
{
WeightedPoint res = new WeightedPoint();
double counter = 0;
foreach (WeightedPoint pt in weightedPoints)
{
res = res.Add(pt.Multiply(pt.Weight));
counter += pt.Weight;
}
res = res.Divide(counter);
return res;
}
