public void ProbabilityMassFunctionTest()
{
double successProbability = 0.42;
var target = new SymmetricGeometricDistribution(successProbability);
double[] expected =
{
0.040973520000000013,
0.070644000000000012,
0.12180000000000002,
0.21,
0.36206896551724133,
0.42,
0.36206896551724133,
0.21,
0.12180000000000002,
0.070644000000000012,
0.040973520000000013,
};
for (int i = -5; i <= 5; i++)
{
double e = expected[i + 5];
double actual = target.ProbabilityMassFunction(i);
Assert.AreEqual(e, actual, 1e-10);
double log = target.LogProbabilityMassFunction(i);
Assert.AreEqual(Math.Log(e), log);
}
}
public void GeometricDistributionConstructorTest()
{
double successProbability = 0.9;
var target = new SymmetricGeometricDistribution(successProbability);
Assert.AreEqual(0.9, target.ProbabilityOfSuccess);
Assert.AreEqual(0, target.Mean);
Assert.AreEqual(0.13580246913580243, target.Variance);
}
public void FitTest()
{
double successProbability = 0;
var target = new SymmetricGeometricDistribution(successProbability);
double[] observations = { 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0 };
double[] weights = null;
IFittingOptions options = null;
Assert.Throws <NotSupportedException>(() => target.Fit(observations, weights, options));
}
public void ConstructorTest()
{
// Create a Geometric distribution with 42% success probability
var dist = new SymmetricGeometricDistribution(probabilityOfSuccess: 0.42);
double mean = dist.Mean; // 1.3809523809523812
Assert.Throws <NotSupportedException>(() => { double d = dist.Median; });
double var = dist.Variance; // 3.2879818594104315
double mode = dist.Mode; // 0
Assert.Throws <NotSupportedException>(() => dist.DistributionFunction(k: 2));
Assert.Throws <NotSupportedException>(() => dist.ComplementaryDistributionFunction(k: 2));
double pdf1 = dist.ProbabilityMassFunction(k: 0); // 0.42
double pdf2 = dist.ProbabilityMassFunction(k: 1); // 0.2436
double pdf3 = dist.ProbabilityMassFunction(k: 2); // 0.141288
double lpdf = dist.LogProbabilityMassFunction(k: 2); // -1.956954918588067
Assert.Throws <NotSupportedException>(() => dist.InverseDistributionFunction(p: 0.17));
Assert.Throws <NotSupportedException>(() => dist.InverseDistributionFunction(p: 0.46));
Assert.Throws <NotSupportedException>(() => dist.InverseDistributionFunction(p: 0.87));
Assert.Throws <NotSupportedException>(() => dist.HazardFunction(x: 0));
Assert.Throws <NotSupportedException>(() => dist.CumulativeHazardFunction(x: 0));
string str = dist.ToString(CultureInfo.InvariantCulture); // "Geometric(x; p = 0.42)"
Assert.AreEqual(0, mean);
Assert.AreEqual(0, mode);
Assert.AreEqual(5.1950113378684817, var);
Assert.AreEqual(0.42, pdf1);
Assert.AreEqual(0.36206896551724133, pdf2);
Assert.AreEqual(0.21, pdf3);
Assert.AreEqual(-1.5606477482646683, lpdf);
Assert.AreEqual("SymmetricGeometric(x; p = 0.42)", str);
}
