/// <summary>
/// Elementary row operation one, interchange two rows
/// </summary>
/// <param name="rowOneIndex">Row one index</param>
/// <param name="rowTwoIndex">Row two index</param>
public static void EROOne(this RealMatrix matrix, int rowOneIndex, int rowTwoIndex)
{
var rowOne = matrix.GetRow(rowOneIndex);
var rowTwo = matrix.GetRow(rowTwoIndex);
for (int i = 0; i < matrix.ColumnCount; i++)
{
matrix.M[rowOneIndex][i] = rowTwo.V[i];
matrix.M[rowTwoIndex][i] = rowOne.V[i];
}
if (matrix.IsAugmentedMatrix)
{
var augmentedRowOne = matrix.GetAugmentedRow(rowOneIndex);
var augmentedRowTwo = matrix.GetAugmentedRow(rowTwoIndex);
for (int i = 0; i < matrix.AugmentedColumnCount; i++)
{
matrix.B[rowOneIndex][i] = augmentedRowOne.V[i];
matrix.B[rowTwoIndex][i] = augmentedRowTwo.V[i];
}
}
matrix.MatrixElementsChanged();
//TODO
//If two rows of A are interchanged to produce a matrix B, then det(B) =
//− det(A).
}
/// <summary>
/// Elemental row operation two, multiply one row with a constant
/// </summary>
/// <param name="rowIndex">Row to multiplt</param>
/// <param name="constant">Multiply row with this constant</param>
public static void EROTwo(this RealMatrix matrix, int rowIndex, IR.RealNumber constant)
{
if (constant == 0)
{
return;
}
var row = matrix.GetRow(rowIndex);
row.ElementMultiplication(constant);
matrix.WriteOnRow(row, rowIndex);
if (matrix.IsAugmentedMatrix)
{
var augmentedRow = matrix.GetAugmentedRow(rowIndex);
augmentedRow.ElementMultiplication(constant);
matrix.WriteOnRow(augmentedRow, rowIndex, isAugmentedRow: true);
}
matrix.MatrixElementsChanged();
//TODO
//If a row of A is multiplied by a real number α to produce a matrix B, then
//det(B) = αdet(A)
}
