% MyMatrix.m     Creation and preservation of matrix AM

AM=[101,102,103,104,105,106,107,108,109;...

    201,202,203,204,205,206,207,208,209;...

    301,302,303,304,305,306,307,308,309];

（2）

（3）

2.4                       二维数组元素的标识

2.4.1                            “全下标”标识

2.4.2                            “单下标”标识

2.4.3                            “逻辑1”标识