I think you mean square matrix, but it isn’t. It’s a vector. For square matrices,
julia> ones(1, 1) / zeros(1, 1)
ERROR: LinearAlgebra.SingularException(1)
Stacktrace:
[1] ldiv!(::LinearAlgebra.Diagonal{Float64,Array{Float64,1}}, ::Array{Float64,2}) at /home/tamas/src/julia-git/usr/share/julia/stdlib/v1.2/LinearAlgebra/src/diagonal.jl:482
[2] \(::LinearAlgebra.Diagonal{Float64,Array{Float64,1}}, ::LinearAlgebra.Adjoint{Float64,Array{Float64,2}}) at /home/tamas/src/julia-git/usr/share/julia/stdlib/v1.2/LinearAlgebra/src/diagonal.jl:489
[3] \(::LinearAlgebra.Adjoint{Float64,Array{Float64,2}}, ::LinearAlgebra.Adjoint{Float64,Array{Float64,2}}) at /home/tamas/src/julia-git/usr/share/julia/stdlib/v1.2/LinearAlgebra/src/generic.jl:962
[4] /(::Array{Float64,2}, ::Array{Float64,2}) at /home/tamas/src/julia-git/usr/share/julia/stdlib/v1.2/LinearAlgebra/src/generic.jl:978
[5] top-level scope at REPL[15]:1