Orthogonal Triangular Decomposition
Why
Well, least squares, for instance.1
Definition
An orthogonal triangular
decomposition (or
orthogonal triangular
factorization) of a $A \in \C ^{m
\times n}$ with $m \geq n$ is an ordered pair
of matrices $(Q, R)$ where $Q$ is orthogonal
and $R$ is upper triangular and
\[
A = QR.
\]
- Future editions will expand this description. ↩︎