scipy.linalg.lapack.dpteqr#

scipy.linalg.lapack.dpteqr(d, e, z, compute_z=0, overwrite_d=0, overwrite_e=0, overwrite_z=0) = <flapack function dpteqr>#

Compute the eigenvalues and optionally the eigenvectors of a positive definite tridiagonal matrix, to high relative accuracy (LAPACK dpteqr).

Parameters:

dndarray: Diagonal of the matrix, length n. Real for every flavor.
endarray: Off-diagonal, length max(0, n - 1). Real for every flavor.
zndarray: Required even when unused. With compute_z=1 it is the matrix whose eigenvectors are wanted, of shape (max(1, n), n); with compute_z=2 its contents are ignored and the eigenvectors of the tridiagonal matrix itself are returned; with compute_z=0 it is not referenced at all and any shape is accepted.
compute_zint, optional: 0 for eigenvalues only, 1 to compute eigenvectors of the original matrix from the z supplied, 2 for eigenvectors of the tridiagonal matrix. Default is 0.
overwrite_dint, optional: If nonzero, d may be overwritten in place. Default is 0.
overwrite_eint, optional: If nonzero, e may be overwritten in place. Default is 0.
overwrite_zint, optional: If nonzero, z may be overwritten in place. Default is 0.

Returns:

dndarray: Eigenvalues in descending order.
endarray: Destroyed by the computation; the contents are not meaningful.
zndarray: Orthonormal eigenvectors as columns, or z unchanged when compute_z is 0.
infoint: 0 on success; if negative, the -info-th argument had an illegal value; if 0 < info <= n, the leading minor of order info is not positive definite; if info > n, that many off-diagonal elements failed to converge to zero.