public void SetupDistributions()
        {
            dists = new IDistribution[8];

            dists[0] = new Beta(1.0, 1.0);
            dists[1] = new ContinuousUniform(0.0, 1.0);
            dists[2] = new Gamma(1.0, 1.0);
            dists[3] = new Normal(0.0, 1.0);
            dists[4] = new Bernoulli(0.6);
            dists[5] = new Weibull(1.0, 1.0);
            dists[6] = new DiscreteUniform(1, 10);
            dists[7] = new LogNormal(1.0, 1.0);
        }

 public void CanSampleSequence()
 {
     var n = new Beta(2.0, 3.0);
     var ied = n.Samples();
     GC.KeepAlive(ied.Take(5).ToArray());
 }

 public void CanSampleSequence()
 {
     var n = new Beta(2.0, 3.0);
     var ied = n.Samples();
     var e = ied.Take(5).ToArray();
 }

 public void CanCreateBeta(double a, double b)
 {
     var n = new Beta(a, b);
     AssertEx.AreEqual<double>(a, n.A);
     AssertEx.AreEqual<double>(b, n.B);
 }

 public void ValidateToString()
 {
     var n = new Beta(1.0, 2.0);
     AssertEx.AreEqual<string>("Beta(A = 1, B = 2)", n.ToString());
 }

 public void ValidateMode(double a, double b, double mode)
 {
     var n = new Beta(a, b);
     AssertEx.AreEqual<double>(mode, n.Mode);
 }

 public void ValidateMedian(double a, double b)
 {
     var n = new Beta(a, 1.0);
     var m = n.Median;
 }

 public void ValidateEntropy(double a, double b, double entropy)
 {
     var n = new Beta(a, b);
     AssertHelpers.AlmostEqual(entropy, n.Entropy, 14);
 }

 public void ValidateMedianThrowsNotSupportedException()
 {
     var n = new Beta(0.0, 1.0);
     Assert.Throws<NotSupportedException>(() => { var m = n.Median; });
 }

 public void ValidateMaximum()
 {
     var n = new Beta(1.0, 1.0);
     Assert.AreEqual(1.0, n.Maximum);
 }

 public void ValidateInverseCumulativeDistribution(double a, double b, double x, double p)
 {
     var dist = new Beta(a, b);
     Assert.That(dist.InverseCumulativeDistribution(p), Is.EqualTo(x).Within(1e-6));
     Assert.That(Beta.InvCDF(a, b, p), Is.EqualTo(x).Within(1e-6));
 }

 public void ValidateDensityLn(double a, double b, double x, double pdfln)
 {
     var n = new Beta(a, b);
     AssertHelpers.AlmostEqualRelative(pdfln, n.DensityLn(x), 13);
     AssertHelpers.AlmostEqualRelative(pdfln, Beta.PDFLn(a, b, x), 13);
 }

 public void ValidateDensity(double a, double b, double x, double pdf)
 {
     var n = new Beta(a, b);
     AssertHelpers.AlmostEqualRelative(pdf, n.Density(x), 12);
     AssertHelpers.AlmostEqualRelative(pdf, Beta.PDF(a, b, x), 12);
 }

 public void ValidateCumulativeDistribution(double a, double b, double x, double p)
 {
     var dist = new Beta(a, b);
     Assert.That(dist.CumulativeDistribution(x), Is.EqualTo(p).Within(1e-13));
     Assert.That(Beta.CDF(a, b, x), Is.EqualTo(p).Within(1e-13));
 }

 public void SetShapeBFailsWithNegativeB()
 {
     var n = new Beta(1.0, 1.0);
     Assert.That(() => n.B = -1.0, Throws.ArgumentException);
 }

 public void ValidateDensity(double a, double b, double x, double pdf)
 {
     var n = new Beta(a, b);
     AssertHelpers.AlmostEqual(pdf, n.Density(x), 13);
 }

 public void ValidateDensityLn(double a, double b, double x, double pdfln)
 {
     var n = new Beta(a, b);
     AssertHelpers.AlmostEqual(pdfln, n.DensityLn(x), 14);
 }

 public void ValidateToString()
 {
     var n = new Beta(1d, 2d);
     Assert.AreEqual("Beta(α = 1, β = 2)", n.ToString());
 }

 public void ValidateMean(double a, double b, double mean)
 {
     var n = new Beta(a, b);
     AssertEx.AreEqual<double>(mean, n.Mean);
 }

 public void ValidateBetaSpecialCaseDensityLn(double x)
 {
     var d = new Dirichlet(new[] { 0.1, 0.3 });
     var beta = new Beta(0.1, 0.3);
     AssertHelpers.AlmostEqualRelative(d.DensityLn(new[] { x }), beta.DensityLn(x), 10);
 }