QRDecomposition

QRDecomposition[m] yields the QR decomposition for a numerical matrix m. The result is a list {q, r}, where q is unitary and r is upper-triangular.

Examples

QR decomposition:

{q, r} = QRDecomposition[{{1, 2}, {3, 4}}]
(* {{{-0.316, -0.949}, {-0.949, 0.316}}, {{-3.16, -4.43}, {0, -0.632}}} *)

Reconstruct:

ConjugateTranspose[q] . r
(* {{1., 2.}, {3., 4.}} *)

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