/// <summary>
/// Generates one sample from the <c>FisherSnedecor</c> distribution without parameter checking.
/// </summary>
/// <param name="rnd">The random number generator to use.</param>
/// <param name="d1">The first degree of freedom (d1) of the distribution. Range: d1 > 0.</param>
/// <param name="d2">The second degree of freedom (d2) of the distribution. Range: d2 > 0.</param>
/// <returns>a <c>FisherSnedecor</c> distributed random number.</returns>
static double SampleUnchecked(System.Random rnd, double d1, double d2)
{
return((ChiSquared.Sample(rnd, d1) * d2) / (ChiSquared.Sample(rnd, d2) * d1));
}
/// <summary>
/// Run example
/// </summary>
/// <seealso cref="http://en.wikipedia.org/wiki/Pearson_product-moment_correlation_coefficient">Pearson product-moment correlation coefficient</seealso>
public void Run()
{
// 1. Initialize the new instance of the ChiSquare distribution class with parameter dof = 5.
var chiSquare = new ChiSquared(5);
Console.WriteLine(@"1. Initialize the new instance of the ChiSquare distribution class with parameter DegreesOfFreedom = {0}", chiSquare.DegreesOfFreedom);
Console.WriteLine(@"{0} distributuion properties:", chiSquare);
Console.WriteLine(@"{0} - Largest element", chiSquare.Maximum.ToString(" #0.00000;-#0.00000"));
Console.WriteLine(@"{0} - Smallest element", chiSquare.Minimum.ToString(" #0.00000;-#0.00000"));
Console.WriteLine(@"{0} - Mean", chiSquare.Mean.ToString(" #0.00000;-#0.00000"));
Console.WriteLine(@"{0} - Median", chiSquare.Median.ToString(" #0.00000;-#0.00000"));
Console.WriteLine(@"{0} - Mode", chiSquare.Mode.ToString(" #0.00000;-#0.00000"));
Console.WriteLine(@"{0} - Variance", chiSquare.Variance.ToString(" #0.00000;-#0.00000"));
Console.WriteLine(@"{0} - Standard deviation", chiSquare.StdDev.ToString(" #0.00000;-#0.00000"));
Console.WriteLine(@"{0} - Skewness", chiSquare.Skewness.ToString(" #0.00000;-#0.00000"));
Console.WriteLine();
// 2. Generate 1000 samples of the ChiSquare(5) distribution
Console.WriteLine(@"2. Generate 1000 samples of the ChiSquare(5) distribution");
var data = new double[1000];
for (var i = 0; i < data.Length; i++)
{
data[i] = chiSquare.Sample();
}
// 3. Get basic statistics on set of generated data using extention methods
Console.WriteLine(@"3. Get basic statistics on set of generated data using extention methods");
Console.WriteLine(@"{0} - Largest element", data.Maximum().ToString(" #0.00000;-#0.00000"));
Console.WriteLine(@"{0} - Smallest element", data.Minimum().ToString(" #0.00000;-#0.00000"));
Console.WriteLine(@"{0} - Mean", data.Mean().ToString(" #0.00000;-#0.00000"));
Console.WriteLine(@"{0} - Median", data.Median().ToString(" #0.00000;-#0.00000"));
Console.WriteLine(@"{0} - Biased population variance", data.PopulationVariance().ToString(" #0.00000;-#0.00000"));
Console.WriteLine(@"{0} - Variance", data.Variance().ToString(" #0.00000;-#0.00000"));
Console.WriteLine(@"{0} - Standard deviation", data.StandardDeviation().ToString(" #0.00000;-#0.00000"));
Console.WriteLine(@"{0} - Biased sample standard deviation", data.PopulationStandardDeviation().ToString(" #0.00000;-#0.00000"));
Console.WriteLine();
// 4. Compute the basic statistics of data set using DescriptiveStatistics class
Console.WriteLine(@"4. Compute the basic statistics of data set using DescriptiveStatistics class");
var descriptiveStatistics = new DescriptiveStatistics(data);
Console.WriteLine(@"{0} - Kurtosis", descriptiveStatistics.Kurtosis.ToString(" #0.00000;-#0.00000"));
Console.WriteLine(@"{0} - Largest element", descriptiveStatistics.Maximum.ToString(" #0.00000;-#0.00000"));
Console.WriteLine(@"{0} - Smallest element", descriptiveStatistics.Minimum.ToString(" #0.00000;-#0.00000"));
Console.WriteLine(@"{0} - Mean", descriptiveStatistics.Mean.ToString(" #0.00000;-#0.00000"));
Console.WriteLine(@"{0} - Variance", descriptiveStatistics.Variance.ToString(" #0.00000;-#0.00000"));
Console.WriteLine(@"{0} - Standard deviation", descriptiveStatistics.StandardDeviation.ToString(" #0.00000;-#0.00000"));
Console.WriteLine(@"{0} - Skewness", descriptiveStatistics.Skewness.ToString(" #0.00000;-#0.00000"));
Console.WriteLine();
// Generate 1000 samples of the ChiSquare(2.5) distribution
var chiSquareB = new ChiSquared(2);
var dataB = new double[1000];
for (var i = 0; i < data.Length; i++)
{
dataB[i] = chiSquareB.Sample();
}
// 5. Correlation coefficient between 1000 samples of ChiSquare(5) and ChiSquare(2.5)
Console.WriteLine(@"5. Correlation coefficient between 1000 samples of ChiSquare(5) and ChiSquare(2.5) is {0}", Correlation.Pearson(data, dataB).ToString("N04"));
Console.WriteLine(@"6. Ranked correlation coefficient between 1000 samples of ChiSquare(5) and ChiSquare(2.5) is {0}", Correlation.Spearman(data, dataB).ToString("N04"));
Console.WriteLine();
// 6. Correlation coefficient between 1000 samples of f(x) = x * 2 and f(x) = x * x
data = Generate.LinearSpacedMap(1000, 0, 100, x => x * 2);
dataB = Generate.LinearSpacedMap(1000, 0, 100, x => x * x);
Console.WriteLine(@"7. Correlation coefficient between 1000 samples of f(x) = x * 2 and f(x) = x * x is {0}", Correlation.Pearson(data, dataB).ToString("N04"));
Console.WriteLine(@"8. Ranked correlation coefficient between 1000 samples of f(x) = x * 2 and f(x) = x * x is {0}", Correlation.Spearman(data, dataB).ToString("N04"));
Console.WriteLine();
}
public void CanSample()
{
var n = new ChiSquared(1.0);
n.Sample();
}
/// <summary>
/// Run example
/// </summary>
/// <a href="http://en.wikipedia.org/wiki/Chi-square_distribution">ChiSquare distribution</a>
public void Run()
{
// 1. Initialize the new instance of the ChiSquare distribution class with parameter dof = 1.
var chiSquare = new ChiSquared(1);
Console.WriteLine(@"1. Initialize the new instance of the ChiSquare distribution class with parameter DegreesOfFreedom = {0}", chiSquare.DegreesOfFreedom);
Console.WriteLine();
// 2. Distributuion properties:
Console.WriteLine(@"2. {0} distributuion properties:", chiSquare);
// Cumulative distribution function
Console.WriteLine(@"{0} - Сumulative distribution at location '0.3'", chiSquare.CumulativeDistribution(0.3).ToString(" #0.00000;-#0.00000"));
// Probability density
Console.WriteLine(@"{0} - Probability density at location '0.3'", chiSquare.Density(0.3).ToString(" #0.00000;-#0.00000"));
// Log probability density
Console.WriteLine(@"{0} - Log probability density at location '0.3'", chiSquare.DensityLn(0.3).ToString(" #0.00000;-#0.00000"));
// Entropy
Console.WriteLine(@"{0} - Entropy", chiSquare.Entropy.ToString(" #0.00000;-#0.00000"));
// Largest element in the domain
Console.WriteLine(@"{0} - Largest element in the domain", chiSquare.Maximum.ToString(" #0.00000;-#0.00000"));
// Smallest element in the domain
Console.WriteLine(@"{0} - Smallest element in the domain", chiSquare.Minimum.ToString(" #0.00000;-#0.00000"));
// Mean
Console.WriteLine(@"{0} - Mean", chiSquare.Mean.ToString(" #0.00000;-#0.00000"));
// Median
Console.WriteLine(@"{0} - Median", chiSquare.Median.ToString(" #0.00000;-#0.00000"));
// Mode
Console.WriteLine(@"{0} - Mode", chiSquare.Mode.ToString(" #0.00000;-#0.00000"));
// Variance
Console.WriteLine(@"{0} - Variance", chiSquare.Variance.ToString(" #0.00000;-#0.00000"));
// Standard deviation
Console.WriteLine(@"{0} - Standard deviation", chiSquare.StdDev.ToString(" #0.00000;-#0.00000"));
// Skewness
Console.WriteLine(@"{0} - Skewness", chiSquare.Skewness.ToString(" #0.00000;-#0.00000"));
Console.WriteLine();
// 3. Generate 10 samples of the ChiSquare distribution
Console.WriteLine(@"3. Generate 10 samples of the ChiSquare distribution");
for (var i = 0; i < 10; i++)
{
Console.Write(chiSquare.Sample().ToString("N05") + @" ");
}
Console.WriteLine();
Console.WriteLine();
// 4. Generate 100000 samples of the ChiSquare(1) distribution and display histogram
Console.WriteLine(@"4. Generate 100000 samples of the ChiSquare(1) distribution and display histogram");
var data = new double[100000];
for (var i = 0; i < data.Length; i++)
{
data[i] = chiSquare.Sample();
}
ConsoleHelper.DisplayHistogram(data);
Console.WriteLine();
// 5. Generate 100000 samples of the ChiSquare(4) distribution and display histogram
Console.WriteLine(@"5. Generate 100000 samples of the ChiSquare(4) distribution and display histogram");
chiSquare.DegreesOfFreedom = 4;
for (var i = 0; i < data.Length; i++)
{
data[i] = chiSquare.Sample();
}
ConsoleHelper.DisplayHistogram(data);
Console.WriteLine();
// 6. Generate 100000 samples of the ChiSquare(8) distribution and display histogram
Console.WriteLine(@"6. Generate 100000 samples of the ChiSquare(8) distribution and display histogram");
chiSquare.DegreesOfFreedom = 8;
for (var i = 0; i < data.Length; i++)
{
data[i] = chiSquare.Sample();
}
ConsoleHelper.DisplayHistogram(data);
}
