//@Override
public DMatrixSparseCSC getQ(DMatrixSparseCSC Q, bool compact)
{
if (Q == null)
{
Q = new DMatrixSparseCSC(1, 1, 0);
}
if (compact)
{
Q.reshape(V.numRows, n, 0);
}
else
{
Q.reshape(V.numRows, m, 0);
}
DMatrixSparseCSC I = CommonOps_DSCC.identity(V.numRows, Q.numCols);
for (int i = V.numCols - 1; i >= 0; i--)
{
QrHelperFunctions_DSCC.rank1UpdateMultR(V, i, beta[i], I, Q, gwork, gx);
I.set(Q);
}
// Apply P transpose to Q
CommonOps_DSCC.permutationInverse(structure.pinv, structureP, V.numRows);
CommonOps_DSCC.permuteRowInv(structureP, Q, I);
// Remove fictitious rows
if (V.numRows > m)
{
CommonOps_DSCC.extractRows(I, 0, m, Q);
}
else
{
Q.set(I);
}
return(Q);
}
private void performDecomposition(DMatrixSparseCSC A)
{
int[] w = gwork.data;
int[] permCol = applyReduce.getArrayQ();
int[] parent = structure.getParent();
int[] leftmost = structure.getLeftMost();
// permutation that was done to ensure all rows have non-zero elements
int[] pinv_structure = structure.getPinv();
int s = m2;
// clear mark nodes. See addRowsInAInToC
//Arrays.fill(w, 0, m2, -1);
for (var i = 0; i < m2; i++)
{
w[i] = -1;
}
//Arrays.fill(x, 0, m2, 0);
Array.Clear(x, 0, m2);
// the counts from structure are actually an upper limit. the actual counts can be lower
R.nz_length = 0;
V.nz_length = 0;
// compute V and R
for (int k = 0; k < n; k++)
{
R.col_idx[k] = R.nz_length;
int p1 = V.col_idx[k] = V.nz_length;
w[k] = k;
V.nz_rows[V.nz_length++] = k; // Add V(k,k) to V's pattern
int top = n;
int col = permCol != null ? permCol[k] : k;
int idx0 = A.col_idx[col];
int idx1 = A.col_idx[col + 1];
for (int p = idx0; p < idx1; p++)
{
int i = leftmost[A.nz_rows[p]];
int len;
for (len = 0; w[i] != k; i = parent[i])
{
w[s + len++] = i;
w[i] = k;
}
while (len > 0)
{
w[s + --top] = w[s + --len];
}
i = pinv_structure[A.nz_rows[p]];
x[i] = A.nz_values[p];
if (i > k && w[i] < k)
{
V.nz_rows[V.nz_length++] = i;
w[i] = k;
}
}
// apply previously computed Householder vectors to the current columns
for (int p = top; p < n; p++)
{
int i = w[s + p];
QrHelperFunctions_DSCC.applyHouseholder(V, i, beta[i], x);
R.nz_rows[R.nz_length] = i;
R.nz_values[R.nz_length++] = x[i];
x[i] = 0;
if (parent[i] == k)
{
ImplSparseSparseMult_DSCC.addRowsInAInToC(V, i, V, k, w);
}
}
for (int p = p1; p < V.nz_length; p++)
{
V.nz_values[p] = x[V.nz_rows[p]];
x[V.nz_rows[p]] = 0;
}
R.nz_rows[R.nz_length] = k;
double max = QrHelperFunctions_DDRM.findMax(V.nz_values, p1, V.nz_length - p1);
if (max == 0.0)
{
singular = true;
R.nz_values[R.nz_length] = 0;
beta[k] = 0;
}
else
{
R.nz_values[R.nz_length] =
QrHelperFunctions_DSCC.computeHouseholder(V.nz_values, p1, V.nz_length, max, Beta);
beta[k] = Beta.value;
}
R.nz_length++;
}
R.col_idx[n] = R.nz_length;
V.col_idx[n] = V.nz_length;
}
