说明：  文件一：由一些较小矩阵（如100个小矩阵），按照大矩阵第一列为矩阵1，第二列为矩阵2，生成,大的下三角矩阵 文件二：求解结构自振频率及振型求解
(File 1: from some smaller matrices (such as 100 small matrices), the first column of the large matrix is matrix 1, and the second column is matrix 2 Document 2: solution of natural frequency and mode shape of structure)