/// <summary>
/// Sets a region of a matrix to the given values.
/// </summary>
///
/// <param name="destination">The matrix where elements will be set.</param>
/// <param name="value">The matrix of values to which matrix elements will be set.</param>
/// <param name="startRow">Starting row index</param>
/// <param name="endRow">End row index</param>
/// <param name="startCol">Starting column index</param>
/// <param name="endCol">End column index</param>
///
public static void Set <T>(this T[,] destination, T value, int startRow, int endRow, int startCol, int endCol)
{
var values = Matrix.Create <T>(destination.Rows(), destination.Columns(), value);
var rowIndices = Accord.Math.Vector.Range(startRow, end(endRow, destination.Rows()));
var columnIndices = Accord.Math.Vector.Range(startCol, end(endCol, destination.Columns()));
set(destination, rowIndices, columnIndices, values, rowIndices, columnIndices);
}
/// <summary>
/// Creates a centering matrix of size <c>N x N</c> in the
/// form <c>(I - 1N)</c> where <c>1N</c> is a matrix with
/// all elements equal to <c>1 / N</c>.
/// </summary>
public static double[,] Centering(int size)
{
if (size < 0)
{
throw new ArgumentOutOfRangeException("size", size,
"The size of the centering matrix must be a positive integer.");
}
double[,] C = Matrix.Create(size, -1.0 / size);
for (int i = 0; i < size; i++)
{
C[i, i] = 1.0 - 1.0 / size;
}
return(C);
}
/// <summary>
/// Sets a region of a matrix to the given values.
/// </summary>
///
/// <param name="destination">The matrix where elements will be set.</param>
/// <param name="value">The value to which matrix elements will be set.</param>
///
public static void Set <T>(this T[,] destination, T value)
{
Set(destination, Matrix.Create(destination.Rows(), destination.Columns(), value));
}
/// <summary>
/// Sets a region of a matrix to the given values.
/// </summary>
///
/// <param name="destination">The matrix where elements will be set.</param>
/// <param name="value">The matrix of values to which matrix elements will be set.</param>
/// <param name="rowIndices">Array of row indices</param>
/// <param name="columnIndices">Array of column indices</param>
///
public static void Set <T>(this T[,] destination, T value, int[] rowIndices, int[] columnIndices)
{
var values = Matrix.Create <T>(destination.Rows(), destination.Columns(), value);
set(destination, rowIndices, columnIndices, values, rowIndices, columnIndices);
}
/// <summary>
/// Sets a region of a matrix to the given values.
/// </summary>
///
/// <param name="destination">The matrix where elements will be set.</param>
/// <param name="value">The matrix of values to which matrix elements will be set.</param>
/// <param name="startRow">Starting row index</param>
/// <param name="endRow">End row index</param>
/// <param name="columnIndices">Array of column indices</param>
///
public static void Set <T>(this T[,] destination, T value, int startRow, int endRow, int[] columnIndices)
{
T[,] source = Matrix.Create(destination.Rows(), destination.Columns(), value);
Set(destination, source, startRow, endRow, columnIndices);
}
/// <summary>
/// Sets a region of a matrix to the given values.
/// </summary>
///
/// <param name="destination">The matrix where elements will be set.</param>
/// <param name="value">The matrix of values to which matrix elements will be set.</param>
/// <param name="rowIndices">Array of row indices</param>
/// <param name="startColumn">Start column index</param>
/// <param name="endColumn">End column index</param>
///
public static void Set <T>(this T[,] destination, T value, int[] rowIndices, int startColumn, int endColumn)
{
T[,] source = Matrix.Create(destination.Rows(), destination.Columns(), value);
Set(destination, source, rowIndices, startColumn, endColumn);
}
/// <summary>
/// Creates a centering matrix of size n x n in the form (I - 1n)
/// where 1n is a matrix with all entries 1/n.
/// </summary>
public static double[,] Centering(int size)
{
return(Matrix.Identity(size).Subtract(Matrix.Create(size, 1.0 / size)));
}