se_Gauss()函数教学函数。高斯消去法，用全选主元高斯消去法求解n阶线性方程组AX = B。其中A=array((0.2368,0.2471,0.2568,1.2671),(0.1968,0.2071,1.2168,0.2271),(0.1581,1.1675,0.1768,0.1871),(1.1161,0.1254,0.1397,0.1490))，B= array(1.8471,1.7471,1.6471,1.5471)