/**
* An upper Hessenberg matrix from the decomposition.
*
* @param H If not null then the results will be stored here. Otherwise a new matrix will be created.
* @return The extracted H matrix.
*/
public DMatrixRMaj getH(DMatrixRMaj H)
{
H = UtilDecompositons_DDRM.checkZeros(H, N, N);
// copy the first row
Array.Copy(QH.data, 0, H.data, 0, N);
for (int i = 1; i < N; i++)
{
for (int j = i - 1; j < N; j++)
{
H.set(i, j, QH.get(i, j));
}
}
return(H);
}
/**
* Extracts the tridiagonal matrix found in the decomposition.
*
* @param T If not null then the results will be stored here. Otherwise a new matrix will be created.
* @return The extracted T matrix.
*/
public DMatrixRMaj getT(DMatrixRMaj T)
{
T = UtilDecompositons_DDRM.checkZeros(T, N, N);
T.data[0] = QT.data[0];
T.data[1] = QT.data[1];
for (int i = 1; i < N - 1; i++)
{
T.set(i, i, QT.get(i, i));
T.set(i, i + 1, QT.get(i, i + 1));
T.set(i, i - 1, QT.get(i - 1, i));
}
T.data[(N - 1) * N + N - 1] = QT.data[(N - 1) * N + N - 1];
T.data[(N - 1) * N + N - 2] = QT.data[(N - 2) * N + N - 1];
return(T);
}
/**
* Extracts the tridiagonal matrix found in the decomposition.
*
* @param T If not null then the results will be stored here. Otherwise a new matrix will be created.
* @return The extracted T matrix.
*/
//@Override
public DMatrixRMaj getT(DMatrixRMaj T)
{
T = UtilDecompositons_DDRM.checkZeros(T, N, N);
T.data[0] = QT.data[0];
for (int i = 1; i < N; i++)
{
T.set(i, i, QT.get(i, i));
double a = QT.get(i - 1, i);
T.set(i - 1, i, a);
T.set(i, i - 1, a);
}
if (N > 1)
{
T.data[(N - 1) * N + N - 1] = QT.data[(N - 1) * N + N - 1];
T.data[(N - 1) * N + N - 2] = QT.data[(N - 2) * N + N - 1];
}
return(T);
}