public void JointDistributionConstructorTest()
{
int[] symbols = { 3, 5 };
JointDistribution target = new JointDistribution(symbols);
double[] p = target.Frequencies;
Assert.AreEqual(3 * 5, p.Length);
for (int i = 0; i < p.Length; i++)
{
p[i] = i;
}
double actual;
actual = target.ProbabilityMassFunction(new int[] { 0, 0 });
Assert.AreEqual(0, actual);
actual = target.ProbabilityMassFunction(new int[] { 0, 1 });
Assert.AreEqual(1, actual);
actual = target.ProbabilityMassFunction(new int[] { 1, 0 });
Assert.AreEqual(5, actual);
actual = target.ProbabilityMassFunction(new int[] { 2, 4 });
Assert.AreEqual(14, actual);
}
public void FitTest2()
{
int[] symbols = { 3, 5 };
JointDistribution target = new JointDistribution(symbols);
double[][] observations =
{
new double[] { 0, 0 },
new double[] { 1, 1 },
new double[] { 2, 1 },
};
double[] weights = { 2, 1, 1 };
target.Fit(observations, weights);
double[] p = target.Frequencies;
double actual;
actual = target.ProbabilityMassFunction(new[] { 0, 0 });
Assert.AreEqual(0.5, actual);
actual = target.ProbabilityMassFunction(new[] { 1, 1 });
Assert.AreEqual(0.25, actual);
actual = target.ProbabilityMassFunction(new[] { 2, 1 });
Assert.AreEqual(0.25, actual);
}
public void UniformTest()
{
int a = 2;
int b = 5;
int n = b - a + 1;
// Wikipedia definitions
double expectedMean = (a + b) / 2.0;
double expectedVar = (System.Math.Pow(b - a + 1, 2) - 1) / 12.0;
double p = 1.0 / n;
JointDistribution dist = JointDistribution.Uniform(1, a, b);
Assert.AreEqual(expectedMean, dist.Mean[0]);
// Assert.AreEqual(expectedVar, dist.Variance);
Assert.AreEqual(n, dist.Frequencies.Length);
Assert.AreEqual(0, dist.ProbabilityMassFunction(new[] { 0 }));
Assert.AreEqual(0, dist.ProbabilityMassFunction(new[] { 1 }));
Assert.AreEqual(p, dist.ProbabilityMassFunction(new[] { 2 }));
Assert.AreEqual(p, dist.ProbabilityMassFunction(new[] { 3 }));
Assert.AreEqual(p, dist.ProbabilityMassFunction(new[] { 4 }));
Assert.AreEqual(p, dist.ProbabilityMassFunction(new[] { 5 }));
Assert.AreEqual(0, dist.ProbabilityMassFunction(new[] { 6 }));
Assert.AreEqual(0, dist.ProbabilityMassFunction(new[] { 7 }));
}
public void ProbabilityMassFunctionTest()
{
JointDistribution dist = JointDistribution.Uniform(1, 2, 5);
double p = 0.25;
Assert.AreEqual(0, dist.ProbabilityMassFunction(new[] { 0 }));
Assert.AreEqual(0, dist.ProbabilityMassFunction(new[] { 1 }));
Assert.AreEqual(p, dist.ProbabilityMassFunction(new[] { 2 }));
Assert.AreEqual(p, dist.ProbabilityMassFunction(new[] { 3 }));
Assert.AreEqual(p, dist.ProbabilityMassFunction(new[] { 4 }));
Assert.AreEqual(p, dist.ProbabilityMassFunction(new[] { 5 }));
Assert.AreEqual(0, dist.ProbabilityMassFunction(new[] { 6 }));
Assert.AreEqual(0, dist.ProbabilityMassFunction(new[] { 7 }));
}