/// <summary>
/// Outer product of two vectors
/// </summary>
/// <param name="u">First vector</param>
/// <param name="v">Second vector</param>
/// <returns>Matrix M[i,j] = u[i]*v[j] </returns>
/// <exception cref="ArgumentNullException">If the u vector is <see langword="null" />.</exception>
/// <exception cref="ArgumentNullException">If the v vector is <see langword="null" />.</exception>
public static Matrix<float> OuterProduct(SparseVector u, SparseVector v)
{
if (u == null)
{
throw new ArgumentNullException("u");
}
if (v == null)
{
throw new ArgumentNullException("v");
}
var matrix = new SparseMatrix(u.Count, v.Count);
for (var i = 0; i < u._storage.ValueCount; i++)
{
for (var j = 0; j < v._storage.ValueCount; j++)
{
if (u._storage.Indices[i] == v._storage.Indices[j])
{
matrix.At(i, j, u._storage.Values[i] * v._storage.Values[j]);
}
}
}
return matrix;
}
/// <summary>
/// Creates a new <see cref="SparseMatrix"/> and inserts the given row at the given index.
/// </summary>
/// <param name="rowIndex">The index of where to insert the row.</param>
/// <param name="row">The row to insert.</param>
/// <returns>A new <see cref="SparseMatrix"/> with the inserted column.</returns>
/// <exception cref="ArgumentNullException">If <paramref name="row"/> is <see langword="null" />. </exception>
/// <exception cref="ArgumentOutOfRangeException">If <paramref name="rowIndex"/> is < zero or > the number of rows.</exception>
/// <exception cref="ArgumentException">If the size of <paramref name="row"/> != the number of columns.</exception>
public override Matrix<float> InsertRow(int rowIndex, Vector<float> row)
{
if (row == null)
{
throw new ArgumentNullException("row");
}
if (rowIndex < 0 || rowIndex > RowCount)
{
throw new ArgumentOutOfRangeException("rowIndex");
}
if (row.Count != ColumnCount)
{
throw new ArgumentException(Resources.ArgumentMatrixSameRowDimension, "row");
}
var result = new SparseMatrix(RowCount + 1, ColumnCount);
for (var i = 0; i < rowIndex; i++)
{
result.At(i, i, At(i, i));
}
result.SetRow(rowIndex, row);
for (var i = rowIndex + 1; i < result.RowCount; i++)
{
result.At(i, i - 1, At(i - 1, i - 1));
}
return result;
}
/// <summary>
/// Create a matrix based on this vector in row form (one single row).
/// </summary>
/// <returns>This vector as a row matrix.</returns>
public override Matrix<float> ToRowMatrix()
{
var matrix = new SparseMatrix(1, Count);
for (var i = 0; i < _storage.ValueCount; i++)
{
matrix.At(0, _storage.Indices[i], _storage.Values[i]);
}
return matrix;
}
/// <summary>
/// Create a matrix based on this vector in column form (one single column).
/// </summary>
/// <returns>This vector as a column matrix.</returns>
public override Matrix<float> ToColumnMatrix()
{
var matrix = new SparseMatrix(Count, 1);
for (var i = 0; i < _storage.ValueCount; i++)
{
matrix.At(_storage.Indices[i], 0, _storage.Values[i]);
}
return matrix;
}
/// <summary>
/// Create a matrix based on this vector in row form (one single row).
/// </summary>
/// <returns>This vector as a row matrix.</returns>
public override Matrix<float> ToRowMatrix()
{
var matrix = new SparseMatrix(1, Count);
for (var i = 0; i < NonZerosCount; i++)
{
matrix.At(0, _nonZeroIndices[i], _nonZeroValues[i]);
}
return matrix;
}
/// <summary>
/// Create a matrix based on this vector in column form (one single column).
/// </summary>
/// <returns>This vector as a column matrix.</returns>
public override Matrix<float> ToColumnMatrix()
{
var matrix = new SparseMatrix(Count, 1);
for (var i = 0; i < NonZerosCount; i++)
{
matrix.At(_nonZeroIndices[i], 0, _nonZeroValues[i]);
}
return matrix;
}
