num::qr

Defined in header <linear/factorization/qr.hpp>

qr_result qr(const mat<real> &A);

Factor \(A\in\mathbb{R}^{m\times n}\) as \(A=QR\).

Picks LAPACK (dgeqrf/dorgqr) if configured, else the in-tree blocked Householder kernel. To force one explicitly, call num::lapack::qr/num::seq::qr.

Return value

qr_result: .Q (orthogonal), .R (upper triangular), with A = Q*R.