Faster matrix product with a specifically structured matrix

[lrnv]

@Sukera

I think you’re confusing columns and rows. Julia is column major, i.e. the first index iterates over columns .

Hum…; This is not concordant with what my machine says:

julia> P = [1 2
       3 4]
2×2 Matrix{Int64}:
 1  2
 3  4

julia> for i in 1:2
       display(P[i,:])
       end
2-element Vector{Int64}:
 1
 2
2-element Vector{Int64}:
 3
 4
julia>