`scipy.linalg._flapack:dstevd`

Summary

Compute the eigenvalues and optionally the eigenvectors of a symmetric tridiagonal matrix by divide-and-conquer (LAPACK dstevd).

d : ndarray: Diagonal elements of the symmetric tridiagonal matrix, length n.
e : ndarray: Off-diagonal elements, length max(n - 1, 1).
compute_v : int, optional: If nonzero, eigenvectors are computed. Default is 1.
lwork : int, optional: Size of the workspace. Default is 1 + 4 * n + n ** 2 when compute_v is nonzero and 1 otherwise, which are the exact requirements.
liwork : int, optional: Size of the integer workspace. Default is 3 + 5 * n when compute_v is nonzero and 1 otherwise.
overwrite_d : int, optional: If nonzero, d may be overwritten in place. Default is 0.
overwrite_e : int, optional: If nonzero, e may be overwritten in place. Default is 0.

vals : ndarray: Eigenvalues in ascending order, written over d.
z : ndarray: Orthonormal eigenvectors as columns, shape (n, n), or a (1, 1) placeholder when compute_v is 0.
info : int: 0 on success; if negative, the -info-th argument had an illegal value; if positive, the algorithm failed to converge.