public void IntervalTest()
{
var target = new UniformDiscreteDistribution(-10, 10);
for (int k = -15; k < 15; k++)
{
double expected = target.ProbabilityMassFunction(k);
double a = target.DistributionFunction(k);
double b = target.DistributionFunction(k - 1);
double c = a - b;
Assert.AreEqual(expected, c, 1e-15);
Assert.AreEqual(c, target.DistributionFunction(k - 1, k), 1e-15);
}
}
public void ConstructorTest()
{
// Create an uniform (discrete) distribution in [2, 6]
var dist = new UniformDiscreteDistribution(a: 2, b: 6);
// Common measures
double mean = dist.Mean; // 4.0
double median = dist.Median; // 4.0
double var = dist.Variance; // 1.3333333333333333
// Cumulative distribution functions
double cdf = dist.DistributionFunction(k: 2); // 0.2
double ccdf = dist.ComplementaryDistributionFunction(k: 2); // 0.8
// Probability mass functions
double pmf1 = dist.ProbabilityMassFunction(k: 4); // 0.2
double pmf2 = dist.ProbabilityMassFunction(k: 5); // 0.2
double pmf3 = dist.ProbabilityMassFunction(k: 6); // 0.2
double lpmf = dist.LogProbabilityMassFunction(k: 2); // -1.6094379124341003
// Quantile function
int icdf1 = dist.InverseDistributionFunction(p: 0.17); // 2
int icdf2 = dist.InverseDistributionFunction(p: 0.46); // 4
int icdf3 = dist.InverseDistributionFunction(p: 0.87); // 6
// Hazard (failure rate) functions
double hf = dist.HazardFunction(x: 4); // 0.5
double chf = dist.CumulativeHazardFunction(x: 4); // 0.916290731874155
// String representation
string str = dist.ToString(CultureInfo.InvariantCulture); // "U(x; a = 2, b = 6)"
Assert.AreEqual(4.0, mean);
Assert.AreEqual(4.0, median);
Assert.AreEqual(1.3333333333333333, var);
Assert.AreEqual(0.916290731874155, chf, 1e-10);
Assert.AreEqual(0.2, cdf);
Assert.AreEqual(0.2, pmf1);
Assert.AreEqual(0.2, pmf2);
Assert.AreEqual(0.2, pmf3);
Assert.AreEqual(-1.6094379124341003, lpmf);
Assert.AreEqual(0.5, hf);
Assert.AreEqual(0.8, ccdf);
Assert.AreEqual(2, icdf1);
Assert.AreEqual(4, icdf2);
Assert.AreEqual(6, icdf3);
Assert.AreEqual("U(x; a = 2, b = 6)", str);
var range1 = dist.GetRange(0.95);
var range2 = dist.GetRange(0.99);
var range3 = dist.GetRange(0.01);
Assert.AreEqual(2, range1.Min);
Assert.AreEqual(6, range1.Max);
Assert.AreEqual(2.0, range2.Min);
Assert.AreEqual(6, range2.Max);
Assert.AreEqual(2.0, range3.Min);
Assert.AreEqual(6, range3.Max);
}