/// <summary>
/// Calculates the median of the given numbers.
/// </summary>
/// <param name="numbers">The numbers whose median is to be calculated.</param>
/// <returns>The median of the given numbers.</returns>
/// <exception cref="System.ArgumentNullException">
/// The specified collection must not be null.
/// </exception>
/// <exception cref="System.InvalidOperationException">
/// The arguments must not be empty.
/// </exception>
public static double Median(IEnumerable <double> numbers)
{
if (numbers == null)
{
throw ArgumentNullException;
}
if (!numbers.Any())
{
throw EmptyNumbersCollectionException;
}
List <double> sortedNumbers = numbers.OrderBy(number => number).ToList();
double median = 0;
if (sortedNumbers.Count % 2 == 0)
{
double lowerMedian = sortedNumbers[sortedNumbers.Count / 2 - 1];
double upperMedian = sortedNumbers[sortedNumbers.Count / 2];
median = ArithmeticMeanCalculator.ArithmeticMean(lowerMedian, upperMedian);
}
else
{
median = sortedNumbers[sortedNumbers.Count / 2];
}
return(median);
}
/// <summary>
/// Calculates the midrange of the specified collection of numbers.
/// </summary>
/// <param name="numbers">The numbers whose midrange is to be calculated.</param>
/// <returns>
/// The midrange of the specified collection of numbers.
/// </returns>
/// <exception cref="System.ArgumentNullException">
/// The specified collection must not be null.
/// </exception>
/// <exception cref="System.InvalidOperationException">
/// The specified collection must not be empty.
/// </exception>
public static double Midrange(IEnumerable <double> numbers)
{
if (numbers == null)
{
throw ArgumentNullException;
}
if (!numbers.Any())
{
throw EmptyNumbersCollectionException;
}
double minValue = numbers.Min();
double maxValue = numbers.Max();
double midrange = ArithmeticMeanCalculator.ArithmeticMean(minValue, maxValue);
return(midrange);
}
/// <summary>
/// Calculates the arithmetic-geometric mean of the specified two numbers.
/// </summary>
/// <param name="x">The first number.</param>
/// <param name="y">The second number.</param>
/// <returns>
/// The arithmetic-geometric mean of the specified two numbers.
/// </returns>
public static double ArithmeticGeometricMean(double x, double y)
{
if (x < 0 || y < 0)
{
throw new InvalidOperationException("Both arguments must be non-negative!");
}
double a_n = 0;
double g_n = 0;
for (int n = 0; n < ApproximationIterations; n++)
{
a_n = ArithmeticMeanCalculator.ArithmeticMean(x, y);
g_n = GeometricMeanCalculator.GeometricMean(x, y);
x = a_n;
y = g_n;
}
return(a_n);
}
