scipy.linalg.lapack.dsbev#
- scipy.linalg.lapack.dsbev(ab, compute_v=1, lower=0, ldab=ab.shape[0], overwrite_ab=0) = <flapack function dsbev>#
Eigenvalues and eigenvectors of a symmetric band matrix (LAPACK
dsbev).sbevdis the divide-and-conquer version and is generally preferred. LAPACK ships no Hermitian counterpart under this name, so only the real flavors exist.- Parameters:
- abndarray
The band of the symmetric/Hermitian matrix, shape
(kd + 1, n): the order n and the bandwidth kd are both read off ab itself. It is consumed rather than returned.- compute_vint, optional
If nonzero, eigenvectors are computed and z is sized for them; otherwise z comes back as a 1x1 placeholder. Default is 1.
- lowerint, optional
If nonzero, ab holds the lower band; otherwise the upper. Default is 0.
- ldabint, optional
Leading dimension of ab. It must equal
ab.shape[0]; the argument exists only because the.pyfexposed it. Default isab.shape[0].- overwrite_abint, optional
If nonzero, ab may be overwritten in place – and it is consumed either way, never returned. Unlike the rest of this module, the default is 1; pass 0 to keep your array intact.
- Returns:
- wndarray
Eigenvalues in ascending order, length
n. Real for every flavor.- zndarray
Eigenvectors as columns, when compute_v asked for them.
- infoint
0 on success; if negative, the
-info-th argument had an illegal value.