/// <summary>
/// The log of the integral of the product of this discrete and that discrete
/// </summary>
/// <param name="that">That discrete distribution</param>
/// <returns>The log inner product</returns>
public double GetLogAverageOf(Discrete that)
{
if (Dimension == 0)
{
return(0);
}
if (that.Dimension == Dimension)
{
if (IsUniform() || that.IsUniform())
{
return(-Math.Log(Dimension)); // the code below does not return this exactly
}
// equivalent to:
// (this*that).GetLogNormalizer() - this.GetLogNormalizer() - that.GetLogNormalizer()
// but that fails if prob[0] == 0
return(Math.Log(prob.Inner(that.prob)));
}
else
{
double sum = 0.0;
int min = Math.Min(prob.Count, that.prob.Count);
for (int i = 0; i < min; i++)
{
sum += prob[i] * that.prob[i];
}
return(Math.Log(sum));
}
}
/// <summary>
/// Returns true if the distribution is uniform.
/// </summary>
/// <returns>True if uniform</returns>
public bool IsUniform()
{
return(disc.IsUniform());
}