/// <summary>
/// Creates a new multidimensional matrix with the same shape as another matrix.
/// </summary>
///
public static Array CreateAs(Array matrix, Type type)
{
int[] outputShape = Matrix.GetShape(matrix, type);
// multidimensional or jagged -> jagged
return(Jagged.Create(elementType: type.GetInnerMostType(), shape: outputShape, value: type.GetDefaultValue()));
}
/// <summary>
/// Creates a square matrix matrix with random data.
/// </summary>
///
public static T[][] Random <T>(int size, IRandomNumberGenerator <T> generator,
bool symmetric = false, T[][] result = null)
{
if (result is null)
{
result = Jagged.Create <T>(size, size);
}
if (!symmetric)
{
for (var i = 0; i < size; i++)
{
result[i] = generator.Generate(size);
}
}
else
{
for (var i = 0; i < size; i++)
{
T[] row = generator.Generate(size / 2, result[i]);
for (int start = 0, end = size - 1; start < size / 2; start++, end--)
{
row[end] = row[start];
}
}
}
return(result);
}
/// <summary>
/// Returns a block-diagonal matrix with the given matrices on its diagonal.
/// </summary>
///
public static T[][] Diagonal <T>(T[][][] blocks)
{
int rows = 0;
int cols = 0;
for (var i = 0; i < blocks.Length; i++)
{
rows += blocks[i].Rows();
cols += blocks[i].Columns();
}
var result = Jagged.Create <T>(rows, cols);
int currentRow = 0;
int currentCol = 0;
for (var i = 0; i < blocks.Length; i++)
{
for (var r = 0; r < blocks[i].Length; r++)
{
for (var c = 0; c < blocks[i][r].Length; c++)
{
result[currentRow + r][currentCol + c] = blocks[i][r][c];
}
}
currentRow = blocks[i].Length;
currentCol = blocks[i][0].Length;
}
return(result);
}
/// <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)
{
T[][] values = Jagged.Create <T>(destination.Rows(), destination.Columns(), value);
int rowIndex = end(endRow, destination.Rows());
int[] rowIndices = Vector.Range(startRow, rowIndex);
int colIndex = end(endCol, destination.Columns());
int[] columnIndices = Vector.Range(startCol, colIndex);
set(destination, rowIndices, columnIndices, values, rowIndices, columnIndices);
}
/// <summary>
/// Creates a rows-by-cols matrix with random data.
/// </summary>
///
public static T[][] Random <T>(int rows, int cols,
IRandomNumberGenerator <T> generator, T[][] result = null)
{
if (result is null)
{
result = Jagged.Create <T>(rows, cols);
}
for (var i = 0; i < rows; i++)
{
result[i] = generator.Generate(cols);
}
return(result);
}
/// <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 = Jagged.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 value to which matrix elements will be set.</param>
///
public static void Set <T>(this T[][] destination, T value)
{
Set(destination, Jagged.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="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)
{
Set(destination, Jagged.Create(destination.Rows(), destination.Columns(), value), rowIndices, startColumn, endColumn);
}
/// <summary>
/// Transforms a vector into a matrix of given dimensions.
/// </summary>
///
public static T[][] Reshape <T>(T[] array, int rows, int cols, MatrixOrder order = MatrixOrder.Default)
{
return(Jagged.Reshape(array, rows, cols, Jagged.Create <T>(rows, cols), order));
}
/// <summary>
/// Creates a matrix of k-hot vectors, where all values at each row are
/// zero except for the indicated <paramref name="indices"/>, which are set to one.
/// </summary>
///
/// <typeparam name="T">The data type for the matrix.</typeparam>
///
/// <param name="indices">The rows's dimension which will be marked as one.</param>
/// <param name="columns">The size (length) of the vectors (columns of the matrix).</param>
///
/// <returns>A matrix containing k-hot vectors where only elements at the indicated
/// <paramref name="indices"/> are set to one and the others are zero.</returns>
///
public static T[][] KHot <T>(int[][] indices, int columns)
{
return(KHot <T>(indices, Jagged.Create <T>(indices.Length, columns)));
}
/// <summary>
/// Returns a matrix with a vector of values on its diagonal.
/// </summary>
///
public static T[][] Diagonal <T>(int rows, int cols, T[] values)
{
return(Diagonal(rows, cols, values, Jagged.Create <T>(rows, cols)));
}
/// <summary>
/// Return a square matrix with a vector of values on its diagonal.
/// </summary>
///
public static T[][] Diagonal <T>(T[] values)
{
return(Diagonal(values, Jagged.Create <T>(values.Length, values.Length)));
}
/// <summary>
/// Returns a square diagonal matrix of the given size.
/// </summary>
///
public static T[][] Diagonal <T>(int size, T value)
{
return(Diagonal(size, value, Jagged.Create <T>(size, size)));
}
/// <summary>
/// Creates a matrix of k-hot vectors, where all values at each row are
/// zero except for the ones in the positions where <paramref name="mask"/>
/// are true, which are set to one.
/// </summary>
///
/// <param name="mask">The boolean mask determining where ones will be placed.</param>
/// <param name="columns">The size (length) of the vectors (columns of the matrix).</param>
///
/// <returns>A matrix containing one-hot vectors where only a single position
/// is one and the others are zero.</returns>
///
public static double[][] KHot(bool[][] mask, int columns)
{
return(KHot(mask, Jagged.Create <double>(mask.Length, columns)));
}
/// <summary>
/// Creates a matrix of k-hot vectors, where all values at each row are
/// zero except for the indicated <paramref name="indices"/>, which are set to one.
/// </summary>
///
/// <param name="indices">The rows's dimension which will be marked as one.</param>
/// <param name="columns">The size (length) of the vectors (columns of the matrix).</param>
///
/// <returns>A matrix containing k-hot vectors where only elements at the indicated
/// <paramref name="indices"/> are set to one and the others are zero.</returns>
///
public static double[][] KHot(int[][] indices, int columns)
{
return(KHot(indices, Jagged.Create <double>(indices.Length, columns)));
}
/// <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 = Jagged.Create <T>(destination.Rows(), destination.Columns(), value);
set(destination, rowIndices, columnIndices, values, rowIndices, columnIndices);
}
/// <summary>
/// Creates a matrix of one-hot vectors, where all values at each row are
/// zero except for the ones in the positions where <paramref name="mask"/>
/// are true, which are set to one.
/// </summary>
///
/// <typeparam name="T">The data type for the matrix.</typeparam>
///
/// <param name="mask">The boolean mask determining where ones will be placed.</param>
///
/// <returns>A matrix containing one-hot vectors where only a single position
/// is one and the others are zero.</returns>
///
public static T[][] OneHot <T>(bool[] mask)
{
return(OneHot <T>(mask, Jagged.Create <T>(mask.Length, 2)));
}