Algorithm 2: Newton–Schulz method.

Input:$A\in {\mathrm{Sym}}_{+}\left(n\right),ϵ>0$    $Y\leftarrow \frac{A}{(1+ϵ)\parallel A\parallel },Z\leftarrow I$    while no convergence do       $T\leftarrow (3I-ZY)/2$       $Y\leftarrow YT,Z\leftarrow TZ$    end while Output:$\sqrt{(1+ϵ)\parallel A\parallel }Y$