Orthogonal matrices and QR factorization
A real orthogonal square matrix Q satisfies QᵀQ=I and preserves Euclidean lengths.
Key knowledge
A real orthogonal square matrix Q satisfies QᵀQ=I and preserves Euclidean lengths. For full-column-rank A∈Rᵐˣⁿ, m≥n, a thin QR factorization A=QR has orthonormal Q columns and nonsingular upper-triangular R.
Conditions and scope
- Use the Euclidean inner product and compatible dimensions.
- QR existence and uniqueness conventions are distinct; diagonal signs can vary.
Sources · 1
References
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Evidence and review
Definitions 3.3.1–3.3.3, Theorems 3.3.1–3.3.2 and thin factorization 3.3.6.
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Entry details
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