public void InverseGammaDistributionConstructorTest2()
        {
            var invGamma = new InverseGammaDistribution(shape: 0.42, scale: 0.5);

            double mean   = invGamma.Mean;                                     // -0.86206896551724133
            double median = invGamma.Median;                                   // 3.1072323347401709
            double var    = invGamma.Variance;                                 // -0.47035626665061164

            double cdf  = invGamma.DistributionFunction(x: 0.27);              // 0.042243552114989695
            double pdf  = invGamma.ProbabilityDensityFunction(x: 0.27);        // 0.35679850067181362
            double lpdf = invGamma.LogProbabilityDensityFunction(x: 0.27);     // -1.0305840804381006
            double ccdf = invGamma.ComplementaryDistributionFunction(x: 0.27); // 0.95775644788501035
            double icdf = invGamma.InverseDistributionFunction(p: cdf);        // 0.26999994629410995

            double hf  = invGamma.HazardFunction(x: 0.27);                     // 0.3725357333377633
            double chf = invGamma.CumulativeHazardFunction(x: 0.27);           // 0.043161763098266373

            string str = invGamma.ToString(CultureInfo.InvariantCulture);      // Γ^(-1)(x; α = 0.42, β = 0.5)

            Assert.AreEqual(-0.86206896551724133, mean);
            Assert.AreEqual(3.1072323347401709, median, 1e-7);
            Assert.AreEqual(-0.47035626665061164, var);
            Assert.AreEqual(0.043161763098266373, chf);
            Assert.AreEqual(0.042243552114989695, cdf, 1e-10);
            Assert.AreEqual(0.35679850067181362, pdf);
            Assert.AreEqual(-1.0305840804381006, lpdf);
            Assert.AreEqual(0.3725357333377633, hf);
            Assert.AreEqual(0.95775644788501035, ccdf);
            Assert.AreEqual(0.27, icdf, 1e-8);
            Assert.AreEqual("Γ^(-1)(x; α = 0.42, β = 0.5)", str);

            double p05 = invGamma.DistributionFunction(median);

            Assert.AreEqual(0.5, p05, 1e-6);
        }
Example #2
0
        public void InverseGammaDistributionConstructorTest2()
        {
            var invGamma = new InverseGammaDistribution(shape: 0.42, scale: 0.5);

            double mean   = invGamma.Mean;                                     // -0.86206896551724133
            double median = invGamma.Median;                                   // 3.1072323347401709
            double var    = invGamma.Variance;                                 // -0.47035626665061164
            double mode   = invGamma.Mode;                                     // 0.35211267605633806

            double cdf  = invGamma.DistributionFunction(x: 0.27);              // 0.042243552114989695
            double pdf  = invGamma.ProbabilityDensityFunction(x: 0.27);        // 0.35679850067181362
            double lpdf = invGamma.LogProbabilityDensityFunction(x: 0.27);     // -1.0305840804381006
            double ccdf = invGamma.ComplementaryDistributionFunction(x: 0.27); // 0.95775644788501035
            double icdf = invGamma.InverseDistributionFunction(p: cdf);        // 0.26999994629410995

            double hf  = invGamma.HazardFunction(x: 0.27);                     // 0.3725357333377633
            double chf = invGamma.CumulativeHazardFunction(x: 0.27);           // 0.043161763098266373

            string str = invGamma.ToString(CultureInfo.InvariantCulture);      // Γ^(-1)(x; α = 0.42, β = 0.5)

            Assert.AreEqual(-0.86206896551724133, mean);
            Assert.AreEqual(3.1072323347401709, median, 1e-7);
            Assert.AreEqual(-0.47035626665061164, var);
            Assert.AreEqual(0.35211267605633806, mode);
            Assert.AreEqual(0.043161763098266373, chf);
            Assert.AreEqual(0.042243552114989695, cdf, 1e-10);
            Assert.AreEqual(0.35679850067181362, pdf);
            Assert.AreEqual(-1.0305840804381006, lpdf);
            Assert.AreEqual(0.3725357333377633, hf);
            Assert.AreEqual(0.95775644788501035, ccdf);
            Assert.AreEqual(0.27, icdf, 1e-7);
            Assert.AreEqual("Γ^(-1)(x; α = 0.42, β = 0.5)", str);

            double p05 = invGamma.DistributionFunction(median);

            Assert.AreEqual(0.5, p05, 1e-6);

            var range1 = invGamma.GetRange(0.95);
            var range2 = invGamma.GetRange(0.99);
            var range3 = invGamma.GetRange(0.01);

            Assert.AreEqual(0.29141691452733387, range1.Min);
            Assert.AreEqual(834.10323133076645, range1.Max);
            Assert.AreEqual(0.16305763832571143, range2.Min);
            Assert.AreEqual(38513.540845383861, range2.Max);
            Assert.AreEqual(0.16305763832571132, range3.Min);
            Assert.AreEqual(38513.540845383861, range3.Max);

            Assert.AreEqual(4.94065645841247E-324, invGamma.Support.Min);
            Assert.AreEqual(double.PositiveInfinity, invGamma.Support.Max);

            Assert.AreEqual(invGamma.InverseDistributionFunction(0), invGamma.Support.Min);
            Assert.AreEqual(invGamma.InverseDistributionFunction(1), invGamma.Support.Max);
        }