解释结构模型(ISM)的matlab学习程序，通过输入邻接矩阵及其维数，计算出因素的分级，以及可达集、先行集和共同集。(Interpretative Structural Model (ISM) in matlab learning program, by entering the adjacency matrix and its dimension, calculate grading factors, as well as arrive set, first set and a common set.)