QR algorithm used for polynomial equation f (x) = x ^ n+ A (1)* x ^ (n

代码说明：

用QR算法求多项式方程f(x)=x^n+a(1)*x^(n-1)+...+a(n-1)*x+a(n)=0的所有根-QR algorithm used for polynomial equation f (x) = x ^ n+ A (1)* x ^ (n-1)+ ...+ A (n-1)* x+ A (n) = 0 for all root