/// <summary>
/// An IEnumerable<double[]> extension method that converts the source into a matrix.
/// </summary>
/// <exception cref="InvalidOperationException">Thrown when the requested operation is invalid.</exception>
/// <param name="source">The source to act on.</param>
/// <param name="vectorType">The <see cref="VectorType"/> of the input array.</param>
/// <returns>e as a Matrix.</returns>
public static Matrix ToMatrix(this IEnumerable <Vector> source, VectorType vectorType = VectorType.Row)
{
var c = source.Count();
if (c == 0)
{
throw new InvalidOperationException("Cannot create matrix from an empty set.");
}
return(Matrix.Stack(vectorType, source.ToArray()));
}
/// <summary>
/// Slices the Matrix returning only the cells specified by their location.
/// </summary>
/// <param name="m">Matrix.</param>
/// <param name="indices">An 2-D location array of indexes to include.</param>
/// <param name="t">Type of the first dimension in the location array.</param>
/// <returns></returns>
public static Matrix Slice(this Matrix m, IEnumerable <IEnumerable <int> > indices, VectorType t = VectorType.Row)
{
List <Vector> vectors = new List <Vector>();
int top = (t == VectorType.Row ? m.Rows : m.Cols);
for (int i = 0; i < top; i++)
{
vectors.Add(m[i, t].Slice(indices.ElementAt(i)));
}
return(Matrix.Stack(t, vectors.ToArray()));
}
/// <summary>Stack a set of vectors into a matrix.</summary>
/// <param name="vectors">.</param>
/// <returns>A Matrix.</returns>
public static Matrix Stack(params Vector[] vectors)
{
return(Matrix.Stack(VectorType.Row, vectors));
}
/// <summary>A Matrix extension method that stacks.</summary>
/// <param name="m">Matrix.</param>
/// <param name="t">Row or Column sum.</param>
/// <returns>A Matrix.</returns>
public static Matrix Stack(this Matrix m, Matrix t)
{
return(Matrix.Stack(m, t));
}
