rows,cols=size(A)

U=copy(A)
L=Matrix{Float16}(I,rows,cols)

for j=1:cols-1
    for i=j+1:rows
        alpha=U[i,j]/U[j,j]
        println("r$i <- r$i - $alpha * r$j")
        U[i,:]=U[i,:]-alpha*U[j,:]
        U[i,j]=0.0
        L[i,j]=alpha
    end
end