More strange things confused me: A column vector isn’t equal to a single-column matrix but a row vector is equal to a single-row matrix.
Why?
julia> col_vec = [1, 2]
2-element Vector{Int64}:
1
2
julia> row_vec = col_vec'
1×2 adjoint(::Vector{Int64}) with eltype Int64:
1 2
julia> one_col_mat = [1; 2;;]
2×1 Matrix{Int64}:
1
2
julia> one_row_mat = [1 2]
1×2 Matrix{Int64}:
1 2
julia> one_col_mat'
1×2 adjoint(::Matrix{Int64}) with eltype Int64:
1 2
julia> one_row_mat'
2×1 adjoint(::Matrix{Int64}) with eltype Int64:
1
2
julia> col_vec == one_col_mat
false
julia> col_vec == one_row_mat'
false
julia> row_vec == one_col_mat'
true
julia> row_vec == one_row_mat
true
julia> one_col_mat == one_row_mat'
true
julia> one_row_mat == one_col_mat'
true