num::qr_factor_blocked

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

template <std::floating_point T>
void qr_factor_blocked(T *A, idx lda, idx m, idx n, T *tau, T *work) noexcept;

Compact Householder QR factorization; reflector tails remain below R's diagonal.

Each panel of qr_block columns is aggregated into a compact-WY block and applied to the trailing columns with two gemms. tau receives min(m, n) scalars; work holds qr_workspace(m, n) elements.