QR with pivoting Node3 geqp3:          QR factor with pivoting, level 3 Node1 QR with pivoting Node1->Node3 Node4 laqp2:          step of geqp3 Node1->Node4 Node5 laqps:          step of geqp3 Node1->Node5 Node2 Orthogonal/unitary factors (QR, CS, etc.) Node2->Node1 .