/// <summary>
/// Postmultiplying this matrix by <c>m</c>.
/// </summary>
/// <param name="m">Matrix to postmultiply by.</param>
/// <returns><c>this</c> * m.</returns>
/// <exception cref="DimensionMismatchException"> if the number of columns of this
/// matrix is not equal to the number of rows of <c>m</c>.</exception>
public Array2DRowFieldMatrix <T> multiply(Array2DRowFieldMatrix <T> m)
{
// safety check
checkMultiplicationCompatible(m);
int nRows = this.getRowDimension();
int nCols = m.getColumnDimension();
int nSum = this.getColumnDimension();
T[][] outData = MathArrays.buildArray(getField(), nRows, nCols);
for (int row = 0; row < nRows; row++)
{
T[] dataRow = data[row];
T[] outDataRow = outData[row];
for (int col = 0; col < nCols; col++)
{
T sum = getField().getZero();
for (int i = 0; i < nSum; i++)
{
sum = sum.add(dataRow[i].multiply(m.data[i][col]));
}
outDataRow[col] = sum;
}
}
return(new Array2DRowFieldMatrix <T>(getField(), outData, false));
}
/// <inheritdoc/>
public FieldMatrix <U> getInverse()
{
int m = pivot.Length;
U one = field.getOne();
FieldMatrix <U> identity = new Array2DRowFieldMatrix <U>(field, m, m);
for (int i = 0; i < m; ++i)
{
identity.setEntry(i, i, one);
}
return(solve(identity));
}
/// <summary>
/// Compute the outer product.
/// </summary>
/// <param name="v">vector with which outer product should be computed</param>
/// <returns>the matrix outer product between instance and v</returns>
public FieldMatrix <T> outerProduct(ArrayFieldVector <T> v)
{
int m = data.Length;
int n = v.data.Length;
FieldMatrix <T> outp = new Array2DRowFieldMatrix <T>(field, m, n);
for (int i = 0; i < m; i++)
{
for (int j = 0; j < n; j++)
{
outp.setEntry(i, j, data[i].multiply(v.data[j]));
}
}
return(outp);
}
/// <inheritdoc/>
public FieldMatrix <T> outerProduct(FieldVector <T> v)
{
try
{
return(outerProduct((ArrayFieldVector <T>)v));
}
catch (InvalidCastException)
{
int m = data.Length;
int n = v.getDimension();
FieldMatrix <T> outp = new Array2DRowFieldMatrix <T>(field, m, n);
for (int i = 0; i < m; i++)
{
for (int j = 0; j < n; j++)
{
outp.setEntry(i, j, data[i].multiply(v.getEntry(j)));
}
}
return(outp);
}
}
/// <summary>
/// Subtract <c>m</c> from this matrix.
/// </summary>
/// <param name="m">Matrix to be subtracted.</param>
/// <returns><c>this</c> + m.</returns>
/// <exception cref="MatrixDimensionMismatchException"> if <c>m</c> is not the same
/// size as this matrix.</exception>
public Array2DRowFieldMatrix <T> subtract(Array2DRowFieldMatrix <T> m)
{
// safety check
checkSubtractionCompatible(m);
int rowCount = getRowDimension();
int columnCount = getColumnDimension();
T[][] outData = MathArrays.buildArray(getField(), rowCount, columnCount);
for (int row = 0; row < rowCount; row++)
{
T[] dataRow = data[row];
T[] mRow = m.data[row];
T[] outDataRow = outData[row];
for (int col = 0; col < columnCount; col++)
{
outDataRow[col] = dataRow[col].subtract(mRow[col]);
}
}
return(new Array2DRowFieldMatrix <T>(getField(), outData, false));
}
