/// <summary>
/// Initializes a new instance of <see cref="TriangularUpper"/> by copying the upper triangle of the provided 2D array.
/// </summary>
/// <param name="array2D">A 2-dimensional array containing the elements of the matrix. Constraints:
/// <paramref name="array2D"/>.GetLength(0) == <paramref name="array2D"/>.GetLength(1).</param>
/// <exception cref="NonMatchingDimensionsException">Thrown if <paramref name="array2D"/>.GetLength(0) !=
/// <paramref name="array2D"/>.GetLength(1).</exception>
public static TriangularUpper CreateFromArray(double[,] array2D)
{
int numRows = array2D.GetLength(0);
int numCols = array2D.GetLength(1);
if (numRows != numCols)
{
string msg = $"Provided array must have the same dimensions, but was ({numRows}x{numCols})";
throw new NonMatchingDimensionsException(msg);
}
return(new TriangularUpper(Conversions.Array2DToPackedUpperColMajor(array2D), numRows));
}
/// <summary>
/// Create a new <see cref="SymmetricMatrix"/> from the lower (subdiagonal) or upper (superdiagonal) portion of the
/// provided array. The array entries will be copied.
/// </summary>
/// <param name="array2D">A 2-dimensional containing the elements of the whole matrix. Its lengths in both dimensions
/// must be the same.</param>
/// <param name="definiteness">If the caller knows that the matrix is positive definite, etc, he can set this property
/// during creation of the <see cref="SymmetricMatrix"/> object.</param>
/// <returns></returns>
public static SymmetricMatrix CreateFromArray(double[,] array2D,
DefiniteProperty definiteness = DefiniteProperty.Unknown)
{
int numRows = array2D.GetLength(0);
int numCols = array2D.GetLength(1);
if (numRows != numCols)
{
string msg = string.Format("Provided array must have the same dimensions, but was ({0}x{1})", numRows, numCols);
throw new NonMatchingDimensionsException(msg);
}
return(new SymmetricMatrix(Conversions.Array2DToPackedUpperColMajor(array2D), numRows, definiteness));
}
