此算法为用于解反问题的lsqr算法，对Ax=b，输入矩阵A，列向量b，以及迭代步数，求得列向量x-This algorithm is used for solution of the inverse problem lsqr algorithm, Ax = b, the input matrix A, the column vector b, as well as the number of iterative steps, to seek the column vector x