/// <summary>
/// Extracts a sub matrix from the current matrix.
/// </summary>
/// <param name="rowIndices">An array of row indices.</param>
/// <param name="colStart">Column index to start extraction from.</param>
/// <param name="colEnd">Column index to end extraction at.</param>
/// <returns>A new <see cref="MatrixD"/> instance containing the extracted sub matrix.</returns>
public MatrixD Submatrix(int[] rowIndices, int colStart, int colEnd)
{
MatrixD result = new MatrixD( rowIndices.Length, (colEnd-colStart)+1 );
for(int r = 0; r < rowIndices.Length; r++)
{
for(int c = colStart; c <= colEnd; c++)
{
result._data[r][c - colStart] = _data[rowIndices[r]][c];
}
}
return result;
}
/// <summary>
/// Initializes a new instance of the <see cref="MatrixD"/> using a given matrix.
/// </summary>
/// <param name="matrix">A <see cref="MatrixD"/> instance.</param>
public MatrixD(MatrixD matrix)
{
_rows = matrix._rows;
_columns= matrix._columns;
_data = (double[][])matrix._data.Clone();
}
/// <summary>
/// Extracts a sub matrix from the current matrix.
/// </summary>
/// <param name="rowIndices">An array of row indices.</param>
/// <param name="colIndices">An array of column indices.</param>
/// <returns>A new <see cref="MatrixD"/> instance containing the extracted sub matrix.</returns>
public MatrixD Submatrix(int[] rowIndices, int[] colIndices)
{
MatrixD result = new MatrixD(rowIndices.Length, colIndices.Length);
for(int r = 0; r < rowIndices.Length; r++)
{
for(int c = 0; c < colIndices.Length; c++)
{
result._data[r][c] = _data[rowIndices[r]][colIndices[c]];
}
}
return result;
}
/// <summary>
/// Extracts a sub matrix from the current matrix.
/// </summary>
/// <param name="rowStart">Row index to start extraction from.</param>
/// <param name="rowEnd">Row index to end extraction at.</param>
/// <param name="colIndices">An array of column indices.</param>
/// <returns>A new <see cref="MatrixD"/> instance containing the extracted sub matrix.</returns>
public MatrixD Submatrix(int rowStart, int rowEnd, int[] colIndices)
{
MatrixD result = new MatrixD( (rowEnd-rowStart)+1, colIndices.Length );
for(int r = rowStart; r <= rowEnd; r++)
{
for(int c = 0; c < colIndices.Length; c++)
{
result._data[r - rowStart][c] = _data[r][colIndices[c]];
}
}
return result;
}
/// <summary>
/// Transposes a matrix.
/// </summary>
/// <param name="m">A <see cref="MatrixD"/> instance.</param>
/// <returns>A new <see cref="MatrixD"/> instance transposed matrix.</returns>
public static MatrixD Transpose(MatrixD m)
{
MatrixD result = new MatrixD(m.Columns, m.Rows);
for(int r = 0; r < m.Rows; r++)
{
for(int c = 0; c < m.Columns; c++)
{
result._data[c][r] = m._data[r][c];
}
}
return result;
}
/// <summary>
/// Extracts a sub matrix from the current matrix.
/// </summary>
/// <param name="rowStart">Row index to start extraction from.</param>
/// <param name="rowEnd">Row index to end extraction at.</param>
/// <param name="colStart">Column index to start extraction from.</param>
/// <param name="colEnd">Column index to end extraction at.</param>
/// <returns>A new <see cref="MatrixD"/> instance containing the extracted sub matrix.</returns>
public MatrixD Submatrix(int rowStart, int rowEnd, int colStart, int colEnd)
{
MatrixD result = new MatrixD( (rowEnd-rowStart)+1 , (colEnd-colStart)+1 );
for (int r = rowStart; r <= rowEnd; r++)
{
for (int c = colStart; c <= colEnd; c++)
{
result._data[r - rowStart][c - colStart] = _data[r][c];
}
}
return result;
}
/// <summary>
/// Subtracts a matrix from a matrix.
/// </summary>
/// <param name="a">A <see cref="MatrixD"/> instance to subtract from.</param>
/// <param name="b">A <see cref="MatrixD"/> instance to subtract.</param>
/// <returns>A new <see cref="MatrixD"/> instance containing the difference.</returns>
/// <remarks>result[x][y] = a[x][y] - b[x][y]</remarks>
/// <exception cref="System.ArgumentException">Matrix dimentions do not match.</exception>
public static MatrixD Subtract(MatrixD a, MatrixD b)
{
if (!MatrixD.EqualDimentions(a,b))
{
throw new ArgumentException("Matrix dimentions do not match.");
}
MatrixD result = new MatrixD(a.Rows, a.Columns);
for(int r = 0; r < a.Rows; r++)
{
for(int c = 0; c < a.Columns; c++)
{
result._data[r][c] = a._data[r][c] - b._data[r][c];
}
}
return result;
}
/// <summary>
/// Subtracts a matrix from a matrix and put the result in a third matrix.
/// </summary>
/// <param name="a">A <see cref="MatrixD"/> instance to subtract from.</param>
/// <param name="b">A <see cref="MatrixD"/> instance to subtract.</param>
/// <param name="result">A <see cref="MatrixD"/> instance to hold the result.</param>
/// <remarks>result[x][y] = a[x][y] - b[x][y]</remarks>
/// <exception cref="System.ArgumentException">Matrix dimentions do not match.</exception>
public static void Subtract(MatrixD a, MatrixD b, MatrixD result)
{
if ((!MatrixD.EqualDimentions(a,b)) && (!MatrixD.EqualDimentions(a,result)))
{
throw new ArgumentException("Matrix dimentions do not match.");
}
for(int r = 0; r < a.Rows; r++)
{
for(int c = 0; c < a.Columns; c++)
{
result._data[r][c] = a._data[r][c] - b._data[r][c];
}
}
}
/// <summary>
/// Multiplies a matrix by a scalar and put the result in a given matrix instance.
/// </summary>
/// <param name="m">A <see cref="MatrixD"/> instance.</param>
/// <param name="s">A double-precision floating point value.</param>
/// <param name="result">A <see cref="MatrixD"/> instance to hold the result.</param>
public static void Multiply(MatrixD m, double s, MatrixD result)
{
Debug.Assert(result.Rows == m.Rows);
Debug.Assert(result.Columns == m.Columns);
for (int i = 0; i < result.Rows; i++)
{
for (int j = 0; j < result.Columns; j++)
{
result._data[i][j] = m._data[i][j] * s;
}
}
}
/// <summary>
/// Negates a matrix.
/// </summary>
/// <param name="m">A <see cref="MatrixD"/> instance.</param>
/// <returns>A new <see cref="MatrixD"/> instance containing the result.</returns>
public static MatrixD Negate(MatrixD m)
{
MatrixD result = new MatrixD(m.Rows, m.Columns);
for(int r = 0; r < result.Rows; r++)
{
for(int c = 0; c < result.Columns; c++)
{
result._data[r][c] = -m._data[r][c];
}
}
return result;
}
/// <summary>
/// Multiplies a matrix by a scalar.
/// </summary>
/// <param name="m">A <see cref="MatrixD"/> instance.</param>
/// <param name="s">A double-precision floating point value.</param>
/// <returns>A new <see cref="MatrixD"/> instance containing the result.</returns>
public static MatrixD Multiply(MatrixD m, double s)
{
MatrixD result = new MatrixD(m);
for (int i = 0; i < result.Rows; i++)
{
for (int j = 0; j < result.Columns; j++)
{
result._data[i][j] *= s;
}
}
return result;
}
/// <summary>
/// Tests whether the dimentions of two given matrices are equal.
/// </summary>
/// <param name="a">A <see cref="MatrixD"/> instance.</param>
/// <param name="b">A <see cref="MatrixD"/> instance.</param>
/// <returns><see langword="true"/> if the dimentions of the two matrices are equal; otherwise, <see langword="false"/>.</returns>
public static bool EqualDimentions(MatrixD a, MatrixD b)
{
if (a.Rows != b.Rows)
return false;
if (a.Columns != b.Columns)
return false;
return true;
}
/// <summary>
/// Multiplies a matrix by a scalar.
/// </summary>
/// <param name="m">A <see cref="MatrixD"/> instance.</param>
/// <param name="s">A double-precision floating point value.</param>
/// <returns>A new <see cref="MatrixD"/> instance containing the result.</returns>
public static MatrixD operator*(double s, MatrixD m)
{
return(MatrixD.Multiply(m, s));
}
/// <summary>
/// Adds two matrices.
/// </summary>
/// <param name="a">A <see cref="MatrixD"/> instance.</param>
/// <param name="b">A <see cref="MatrixD"/> instance.</param>
/// <returns>A new <see cref="MatrixD"/> instance containing the sum.</returns>
public static MatrixD operator+(MatrixD a, MatrixD b)
{
return(MatrixD.Add(a, b));
}
/// <summary>
/// Negates the values of a matrix.
/// </summary>
/// <param name="m">A <see cref="MatrixD"/> instance.</param>
/// <returns>A new <see cref="MatrixD"/> instance containing the result.</returns>
public static MatrixD operator-(MatrixD m)
{
return(MatrixD.Negate(m));
}