From 48d6d2757be315d21a0638de37d13d5661bb656f Mon Sep 17 00:00:00 2001 From: StephenVavasis Date: Tue, 7 Aug 2018 12:19:29 -0400 Subject: [PATCH] update docstring for qr (#28446) * update docstring for qr Explain in docstring how to obtain both the thin and full factors. This is related to issue https://github.com/JuliaLang/julia/issues/27397. * further improvement/clarification --- stdlib/LinearAlgebra/src/qr.jl | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/stdlib/LinearAlgebra/src/qr.jl b/stdlib/LinearAlgebra/src/qr.jl index 9f32d7c8d530e1..dab6bd6a88912b 100644 --- a/stdlib/LinearAlgebra/src/qr.jl +++ b/stdlib/LinearAlgebra/src/qr.jl @@ -322,7 +322,10 @@ solution and if the solution is not unique, the one with smallest norm is return Multiplication with respect to either full/square or non-full/square `Q` is allowed, i.e. both `F.Q*F.R` and `F.Q*A` are supported. A `Q` matrix can be converted into a regular matrix with -[`Matrix`](@ref). +[`Matrix`](@ref). This operation returns the "thin" Q factor, i.e., if `A` is `m`×`n` with `m>=n`, then +`Matrix(F.Q)` yields an `m`×`n` matrix with orthonormal columns. To retrieve the "full" Q factor, an +`m`×`m` orthogonal matrix, use `F.Q*Matrix(I,m,m)`. If `m<=n`, then `Matrix(F.Q)` yields an `m`×`m` +orthogonal matrix. # Examples ```jldoctest