/// <summary>
/// Sets the parameters to represent the weighted sum of two discrete distributions.
/// </summary>
/// <param name="dist1">The first discrete distribution. Can be the same object as <c>this</c></param>
/// <param name="weight1">The first weight</param>
/// <param name="dist2">The second discrete distribution. Cannot be the same object as <c>this</c></param>
/// <param name="weight2">The second weight</param>
public void SetToSum(double weight1, Discrete dist1, double weight2, Discrete dist2)
{
if (weight1 + weight2 == 0)
{
SetToUniform();
}
else if (weight1 + weight2 < 0)
{
throw new ArgumentException("weight1 (" + weight1 + ") + weight2 (" + weight2 + ") < 0");
}
else if (weight1 == 0)
{
SetTo(dist2);
}
else if (weight2 == 0)
{
SetTo(dist1);
}
// if dist1 == dist2 then we must return dist1, with no roundoff error
else if (dist1.Equals(dist2))
{
SetTo(dist1);
}
else if (double.IsPositiveInfinity(weight1))
{
if (double.IsPositiveInfinity(weight2))
{
throw new ArgumentException("both weights are infinity");
}
else
{
SetTo(dist1);
}
}
else if (double.IsPositiveInfinity(weight2))
{
SetTo(dist2);
}
else
{
dist1.GetProbs(prob);
if (dist2.IsPointMass)
{
prob.Scale(weight1);
prob[dist2.Point] += weight2;
}
else if (dist2.Dimension < this.Dimension)
{
Vector prob2 = Vector.Zero(prob.Count, prob.Sparsity);
dist2.GetProbs(prob2);
prob.SetToSum(weight1, prob, weight2, prob2);
}
else
{
prob.SetToSum(weight1, prob, weight2, dist2.prob);
}
Normalize();
}
}
/// <summary>
/// Override of the Equals method
/// </summary>
/// <param name="obj">The instance to compare to</param>
/// <returns>True if the two distributions are the same in value, false otherwise</returns>
/// <exclude/>
public override bool Equals(object obj)
{
var db = obj as TThis;
if (db == null)
{
return(false);
}
return(disc.Equals(db.disc));
}