If you call lu on an SMatrix, you get a static LU factorization—cool: using StaticArrays using LinearAlgebra A = SMatrix{3, 3}(rand(3, 3)) lu(A) # StaticArrays.LU # L factor: # 3×3 LowerTriangular{Float64, SMatrix{3, 3, Float64, 9}}: # 1.0 ⋅ ⋅ # 0.706739 1.0 ⋅ # 0.64896…

[image] maxkapur: But sometimes, you want to preallocate space for the L and U factors. Preallocation doesn’t make sense for SMatrix — there is no “allocation” cost in the first place. So what is your motivation?

For small matrices, won’t my_LU \ b benefit from having my_LU as an SArray for the same reason that A \ b does? (Or is the latter assumption also incorrect?)

lu(smatrix) already returns L and U factors that are backed by SMatrix. What more do you want? (Note that StaticArrays already has optimized methods for triangular solves with SMatrix storage.)

How to preallocate a static array for use with `lu!`

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How to preallocate a static array for use with `lu!`

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