why is this not possible?
Given
typeof((u₁,u₂))
Tuple{Vector{SVector{3, Float64}}, Vector{SVector{3, Float64}}}
and
typeof(M)
MMatrix{8, 9, Float64, 72} (alias for MArray{Tuple{8, 9}, Float64, 2, 72})
I want to fill M,
zs = @SVector zeros(eltype(M))
odd_rows(u₁,u₂) = SVector{9}(u₁.data...,zs...,(u₂[1]*u₁).data...)
map!(odd_rows,eachrow(M),u₁,u₂)
Extending this, can a row iterator server as an lvalue to mutate the underlying matrix?