用高斯－约当消去法求解A[XY]=[BI].由于消去过程是在全矩阵中选主元来进行的，故可使舍入误差对结果的影响减到最小-Using Gauss- Jordan elimination method to solve A [XY] = [BI]. Since the elimination process is selected in the whole matrix of the PCA to carry out, it will enable the rounding error on the