sparse的使用方法，每次使用都忘记，这几转载过来

最新推荐文章于 2024-08-27 08:26:30 发布

翻译最新推荐文章于 2024-08-27 08:26:30 发布 · 581 阅读

本文深入解析MATLAB中sparse函数用于创建稀疏矩阵的过程，详细阐述了输入参数i、j、s、m、n和nz_max的意义，并通过实例展示了如何在MATLAB中实现这一操作。

MATLAB provides a sparse function of the form

matrix = sparse ( i, j, s, m, n, nz_max )

This function can be used to create a sparse matrix. The input arguments have the following meaning:

i：the row indices of the nonzero elements;

j：the column indices of the nonzero elements;

s：the values of the nonzero elements;

m： the number of rows in the matrix;%所要创建的稀疏矩阵的行数

n：the number of columns in the matrix;%所要创建的稀疏矩阵的列数

nz_max：the maximum number of nonzero elements in the matrix; nz_max is commonly omitted, in which case its value is taken from the length of s.

Note that nz_max is commonly omitted, in which case its value is taken from the length of s. Moreover, if you specify nz_max explicitly, or implicitly through the size of s, MATLAB will allow you to increase the number of nonzero elements at any time. Specifying nz_max correctly, then, is simply a matter of efficiency.

使用例子：稀疏矩阵如下

 	11  12   0   0  15
         0  22  23   0   0
        31   0  33  34  35

在matlab中输入如下参数：

  	i = [  1,  1,  1,  2,  2,  3,  3,  3,  3 ];%注意当i和j有重复的下表时候，稀疏矩阵会相加s中的值
        j = [  1,  2,  5,  2,  3,  1,  3,  4,  5 ];
        s = [ 11, 12, 15, 22, 23, 31, 33, 34, 35 ];
        m = 3;
        n = 5;
        nz_max = 9;

        a = sparse ( i, j, s, m, n, nz_max );