采用预处理的CG算法求解Hilbert矩阵，求解1000阶及以上的方程组。预处理矩阵分别采用3对角线、5对角线以及在对角线上分割小块矩阵的矩阵。可以任意设置收敛精度，简单实用。-CG algorithm for solving Hilbert matrix preconditioning, 1000 order and above solving equations. Diagonal matrix were pretreated with 3, 5 and in the diagonal ma