claed0 (l)  Linux Man Pages
claed0: the divide and conquer method, CLAED0 computes all eigenvalues of a symmetric tridiagonal matrix which is one diagonal block of those from reducing a dense or band Hermitian matrix and corresponding eigenvectors of the dense or band matrix
Command to display claed0
manual in Linux: $ man l claed0
NAME
CLAED0  the divide and conquer method, CLAED0 computes all eigenvalues of a symmetric tridiagonal matrix which is one diagonal block of those from reducing a dense or band Hermitian matrix and corresponding eigenvectors of the dense or band matrix
SYNOPSIS
 SUBROUTINE CLAED0(

QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, RWORK,
IWORK, INFO )

INTEGER
INFO, LDQ, LDQS, N, QSIZ

INTEGER
IWORK( * )

REAL
D( * ), E( * ), RWORK( * )

COMPLEX
Q( LDQ, * ), QSTORE( LDQS, * )
PURPOSE
Using the divide and conquer method, CLAED0 computes all eigenvalues
of a symmetric tridiagonal matrix which is one diagonal block of
those from reducing a dense or band Hermitian matrix and
corresponding eigenvectors of the dense or band matrix.
ARGUMENTS
 QSIZ (input) INTEGER

The dimension of the unitary matrix used to reduce
the full matrix to tridiagonal form. QSIZ >= N if ICOMPQ = 1.
 N (input) INTEGER

The dimension of the symmetric tridiagonal matrix. N >= 0.
 D (input/output) REAL array, dimension (N)

On entry, the diagonal elements of the tridiagonal matrix.
On exit, the eigenvalues in ascending order.
 E (input/output) REAL array, dimension (N1)

On entry, the offdiagonal elements of the tridiagonal matrix.
On exit, E has been destroyed.
 Q (input/output) COMPLEX array, dimension (LDQ,N)

On entry, Q must contain an QSIZ x N matrix whose columns
unitarily orthonormal. It is a part of the unitary matrix
that reduces the full dense Hermitian matrix to a
(reducible) symmetric tridiagonal matrix.
 LDQ (input) INTEGER

The leading dimension of the array Q. LDQ >= max(1,N).
 IWORK (workspace) INTEGER array,

the dimension of IWORK must be at least
6 + 6*N + 5*N*lg N
( lg( N ) = smallest integer k
such that 2^k >= N )
 RWORK (workspace) REAL array,

dimension (1 + 3*N + 2*N*lg N + 3*N**2)
( lg( N ) = smallest integer k
such that 2^k >= N )
QSTORE (workspace) COMPLEX array, dimension (LDQS, N)
Used to store parts of
the eigenvector matrix when the updating matrix multiplies
take place.
 LDQS (input) INTEGER

The leading dimension of the array QSTORE.
LDQS >= max(1,N).
 INFO (output) INTEGER

= 0: successful exit.
< 0: if INFO = i, the ith argument had an illegal value.
> 0: The algorithm failed to compute an eigenvalue while
working on the submatrix lying in rows and columns
INFO/(N+1) through mod(INFO,N+1).
Pages related to claed0
 claed0 (3)
 claed7 (l)  computes the updated eigensystem of a diagonal matrix after modification by a rankone symmetric matrix
 claed8 (l)  merges the two sets of eigenvalues together into a single sorted set
 claein (l)  uses inverse iteration to find a right or left eigenvector corresponding to the eigenvalue W of a complex upper Hessenberg matrix H
 claesy (l)  computes the eigendecomposition of a 2by2 symmetric matrix ( ( A, B );( B, C ) ) provided the norm of the matrix of eigenvectors is larger than some threshold value
 claev2 (l)  computes the eigendecomposition of a 2by2 Hermitian matrix [ A B ] [ CONJG(B) C ]
 cla_gbamv (l)  performs one of the matrixvector operations y := alpha*abs(A)*abs(x) + beta*abs(y),
 cla_gbrcond_c (l)  CLA_GBRCOND_C Compute the infinity norm condition number of op(A) * inv(diag(C)) where C is a REAL vector