private static void PermutationParityTest()
{
RowPermutation <Real> perm = new RowPermutation <Real>(2, 4, 1, 3, 0);
Console.WriteLine("Parity:");
Console.WriteLine(perm.Signature);
}
public LUPDecomposition(Matrix <T> mat)
{
UpperMatrix = mat.EchelonForm;
LowerMatrix = new Matrix <T>(mat.Rows, Math.Min(mat.Rows, mat.Columns));
List <IMatrixOperation <T> > reductionOps = new List <IMatrixOperation <T> >(mat.EchelonFormReductionOperations);
reductionOps.Reverse();
for (int i = 0; i < Math.Min(LowerMatrix.Rows, LowerMatrix.Columns); i++)
{
LowerMatrix[i, i] = Field <T> .One;
}
int[] permArr = new int[mat.Rows];
for (int i = 0; i < mat.Rows; i++)
{
permArr[i] = i;
}
Permutation = new RowPermutation <T>(permArr);
foreach (IMatrixOperation <T> op in reductionOps)
{
if (op is SwapRows <T> swapOp)
{
int temp = Permutation.IndexList[swapOp.FirstRowIndex];
Permutation.IndexList[swapOp.FirstRowIndex] = Permutation.IndexList[swapOp.SecondRowIndex];
Permutation.IndexList[swapOp.SecondRowIndex] = temp;
}
else
{
op.InverseApplyTo(LowerMatrix);
}
}
}
public LUPDecomposition(LUPDecomposition <T> other)
{
UpperMatrix = new Matrix <T>(other.UpperMatrix);
LowerMatrix = new Matrix <T>(other.LowerMatrix);
Permutation = new RowPermutation <T>(other.Permutation.IndexList.ToArray());
}