The "economy" option can be used in SPQR to compute a QR factorization of a (m x n) matrix with m < n consisting of blocks Q_1, and Q_2, where Q_1 has as shape of (m x n) and Q_2 of (m x k - n). For k = n we get the reduced form, for k = m the full one. For k in between m and n, SPQR yields a block that spans part of the kernel of A. This patch adds this functionality to PySPQR.
The "economy" option can be used in SPQR to compute a QR factorization of a (m x n) matrix with m < n consisting of blocks Q_1, and Q_2, where Q_1 has as shape of (m x n) and Q_2 of (m x k - n). For k = n we get the reduced form, for k = m the full one. For k in between m and n, SPQR yields a block that spans part of the kernel of A. This patch adds this functionality to PySPQR.