scipy.sparse.linalg.eigsh

scipy.sparse.linalg.eigsh(A, k=6, M=None, sigma=None, which='LM', v0=None, ncv=None, maxiter=None, tol=0, return_eigenvectors=True, Minv=None, OPinv=None, mode='normal')
功能：Find k eigenvalues and eigenvectors of the real symmetric square matrix or complex hermitian matrix A.-找到实对称方阵或复杂厄米特矩阵的k个特征值特征向量
（厄米特矩阵（Hermitian Matrix，又译作“埃尔米特矩阵”或“厄米矩阵”），指的是自共轭矩阵。矩阵中每一个第i行第j列的元素都与第j行第i列的元素的共轭相等。埃尔米特矩阵主对角线上的元素都是实数的，其特征值也是实数。）

Parameters：
A：ndarray, sparse matrix or LinearOperator
A square operator representing the operation A * x, where A is real symmetric or complex hermitian. For buckling mode (see below) A must additionally be positive-definite.

k：int, optional
The number of eigenvalues and eigenvectors desired. k must be smaller than N. It is not possible to compute all eigenvectors of a matrix.

Returns：
w：array
Array of k eigenvalues.

v：array
An array representing the k eigenvectors. The column v[:, i] is the eigenvector corresponding to the eigenvalue w[i].

参考：https://docs.scipy.org/doc/scipy/reference/generated/scipy.sparse.linalg.eigsh.html