/// <summary>
/// Outer product of two vectors; Sets <i>A[i,j] = x[i] * y[j]</i>.
/// </summary>
/// <param name="x">the first source vector.</param>
/// <param name="y">the second source vector.</param>
/// <param name="A">the matrix to hold the resultsd Set this parameter to <i>null</i> to indicate that a new result matrix shall be constructed.</param>
/// <returns>A (for convenience only).</returns>
public static DoubleMatrix2D MultOuter(DoubleMatrix1D x, DoubleMatrix1D y, DoubleMatrix2D A)
{
int rows = x.Size;
int columns = y.Size;
if (A == null)
{
A = x.Like2D(rows, columns);
}
if (A.Rows != rows || A.Columns != columns)
{
throw new ArgumentException();
}
for (int row = rows; --row >= 0;)
{
A.ViewRow(row).Assign(y);
}
for (int column = columns; --column >= 0;)
{
A.ViewColumn(column).Assign(x, BinaryFunctions.Mult);
}
return(A);
}
/// <summary>
/// Returns a string representation of the given matrix.
/// </summary>
/// <param name="matrix">
/// The matrix to convert.
/// </param>
/// <returns>
/// A string representation of the given matrix.
/// </returns>
public string ToString(DoubleMatrix1D matrix)
{
DoubleMatrix2D easy = matrix.Like2D(1, matrix.Size);
easy.ViewRow(0).Assign(matrix);
return(ToString(easy));
}
/// <summary>
/// Outer product of two vectors; Returns a matrix with <i>A[i,j] = x[i] * y[j]</i>.
/// </summary>
/// <param name="x">the first source vector.</param>
/// <param name="y">the second source vector.</param>
/// <returns>the outer product </i>A</i>.</returns>
private static DoubleMatrix2D XMultOuter(DoubleMatrix1D x, DoubleMatrix1D y)
{
DoubleMatrix2D A = x.Like2D(x.Size, y.Size);
MultOuter(x, y, A);
return(A);
}