QR decomposition in julia 2x slower than octave

General Usage Performance
3

I suspect they may be doing different things. I don’t know what qr method Octave calls when no output arguments are provided, but my guess is that it’s just doing the 1st phase (computing the Householder reflectors and upper-triangular part) and not the 2nd (building Q). This would roughly match qrfact in Julia. On my machine, I get:

julia> @time qrfact(A);
  5.906331 seconds (25.99 k allocations: 194.912 MiB, 2.13% gc time)

julia> @time qr(A);
 16.202900 seconds (93.73 k allocations: 770.718 MiB, 1.62% gc time)
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