/// <include file='FactorDocs.xml' path='factor_docs/message_op_class[@name="IsGreaterThanOp"]/message_doc[@name="AAverageConditional(Bernoulli, Poisson, int)"]/*'/>
public static Poisson BAverageConditional([SkipIfUniform] Bernoulli isGreaterThan, int a, [Proper] Poisson b)
{
if (b.IsPointMass || !b.IsProper())
{
return(Poisson.Uniform());
}
double bMean = b.GetMean();
double sum = 0;
double bsum = 0;
if (b.Precision == 1)
{
if (a > 0)
{
sum = MMath.GammaUpper(a, b.Rate);
bsum = (sum - Math.Exp(b.GetLogProb(a - 1))) * b.Rate;
}
}
else
{
for (int i = 0; i < a; i++)
{
double p = Math.Exp(b.GetLogProb(i));
sum += p;
bsum += i * p;
}
if (sum > 1)
{
sum = 1; // this can happen due to round-off errors
}
if (bsum > bMean)
{
bsum = bMean;
}
}
double pT = isGreaterThan.GetProbTrue();
double pF = 1 - pT;
double Z = pT * sum + pF * (1 - sum);
double bZ = pT * bsum + pF * (bMean - bsum);
Poisson result = new Poisson(bZ / Z);
result.SetToRatio(result, b, false);
return(result);
}
/// <include file='FactorDocs.xml' path='factor_docs/message_op_class[@name="IsGreaterThanOp"]/message_doc[@name="AAverageConditional(Bernoulli, Poisson, int)"]/*'/>
public static Poisson AAverageConditional([SkipIfUniform] Bernoulli isGreaterThan, [Proper] Poisson a, int b)
{
if (a.IsPointMass || !a.IsProper())
{
return(Poisson.Uniform());
}
double aMean = a.GetMean();
double sum = 0;
double asum = 0;
if (a.Precision == 1)
{
if (b >= 0)
{
sum = MMath.GammaUpper(b + 1, a.Rate);
asum = (sum - Math.Exp(a.GetLogProb(b))) * a.Rate;
}
}
else
{
for (int i = 0; i <= b; i++)
{
double p = Math.Exp(a.GetLogProb(i));
sum += p;
asum += i * p;
}
if (sum > 1)
{
sum = 1; // this can happen due to round-off errors
}
if (asum > aMean)
{
asum = aMean;
}
}
double pT = isGreaterThan.GetProbTrue();
double pF = 1 - pT;
double Z = pF * sum + pT * (1 - sum);
double aZ = pF * asum + pT * (aMean - asum);
Poisson result = new Poisson(aZ / Z);
result.SetToRatio(result, a, false);
return(result);
}
