public static void Main(string[] args)
{
IntIntToDoubleFunction ptr = NthPower;
int x = 10, y = 3;
Console.WriteLine($"{x}^{y} = {ptr(x, y)}"); // whoa.
ptr = NthRoot;
Console.WriteLine($"{y}th root of {x} = {ptr(x, y)}");
// delegates are first class citizens: they can be assigned to variables,
// passed as parameters, returned from functions.
double res = ApplyFunction(
new IntIntToDoubleFunction(Product), // this is the OLD C# syntax
x, y);
// Newer versions of C# create the "new IntIntToDoubleFunction" implicitly:
res = ApplyFunction(Product, x, y);
}
//-------------------------------------------------------------------------
/// <summary>
/// Obtains an instance with entries filled using a function.
/// <para>
/// The function is passed the row and column index, returning the value.
///
/// </para>
/// </summary>
/// <param name="rows"> the number of rows </param>
/// <param name="columns"> the number of columns </param>
/// <param name="valueFunction"> the function used to populate the value </param>
/// <returns> a matrix initialized using the function </returns>
public static DoubleMatrix of(int rows, int columns, IntIntToDoubleFunction valueFunction)
{
if (rows == 0 || columns == 0)
{
return(EMPTY);
}
//JAVA TO C# CONVERTER NOTE: The following call to the 'RectangularArrays' helper class reproduces the rectangular array initialization that is automatic in Java:
//ORIGINAL LINE: double[][] array = new double[rows][columns];
double[][] array = RectangularArrays.ReturnRectangularDoubleArray(rows, columns);
for (int i = 0; i < array.Length; i++)
{
double[] inner = array[i];
for (int j = 0; j < inner.Length; j++)
{
inner[j] = valueFunction(i, j);
}
}
return(new DoubleMatrix(array, rows, columns));
}
public static double ApplyFunction(IntIntToDoubleFunction fn, int x, int y)
{
return(fn(x, y));
}
