LAPACK 3.11.0
LAPACK: Linear Algebra PACKage
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subroutine dsterf | ( | integer | N, |
double precision, dimension( * ) | D, | ||
double precision, dimension( * ) | E, | ||
integer | INFO | ||
) |
DSTERF
Download DSTERF + dependencies [TGZ] [ZIP] [TXT]
DSTERF computes all eigenvalues of a symmetric tridiagonal matrix using the Pal-Walker-Kahan variant of the QL or QR algorithm.
[in] | N | N is INTEGER The order of the matrix. N >= 0. |
[in,out] | D | D is DOUBLE PRECISION array, dimension (N) On entry, the n diagonal elements of the tridiagonal matrix. On exit, if INFO = 0, the eigenvalues in ascending order. |
[in,out] | E | E is DOUBLE PRECISION array, dimension (N-1) On entry, the (n-1) subdiagonal elements of the tridiagonal matrix. On exit, E has been destroyed. |
[out] | INFO | INFO is INTEGER = 0: successful exit < 0: if INFO = -i, the i-th argument had an illegal value > 0: the algorithm failed to find all of the eigenvalues in a total of 30*N iterations; if INFO = i, then i elements of E have not converged to zero. |