Provided by: liblapack-doc_3.3.1-1_all bug

NAME

       LAPACK-3  -  computes  all  eigenvalues  and, optionally, eigenvectors of a real symmetric
       tridiagonal matrix A

SYNOPSIS

       SUBROUTINE SSTEV( JOBZ, N, D, E, Z, LDZ, WORK, INFO )

           CHARACTER     JOBZ

           INTEGER       INFO, LDZ, N

           REAL          D( * ), E( * ), WORK( * ), Z( LDZ, * )

PURPOSE

       SSTEV  computes  all  eigenvalues  and,  optionally,  eigenvectors  of  a  real  symmetric
       tridiagonal matrix A.

ARGUMENTS

        JOBZ    (input) CHARACTER*1
                = 'N':  Compute eigenvalues only;
                = 'V':  Compute eigenvalues and eigenvectors.

        N       (input) INTEGER
                The order of the matrix.  N >= 0.

        D       (input/output) REAL array, dimension (N)
                On entry, the n diagonal elements of the tridiagonal matrix
                A.
                On exit, if INFO = 0, the eigenvalues in ascending order.

        E       (input/output) REAL array, dimension (N-1)
                On entry, the (n-1) subdiagonal elements of the tridiagonal
                matrix A, stored in elements 1 to N-1 of E.
                On exit, the contents of E are destroyed.

        Z       (output) REAL array, dimension (LDZ, N)
                If JOBZ = 'V', then if INFO = 0, Z contains the orthonormal
                eigenvectors of the matrix A, with the i-th column of Z
                holding the eigenvector associated with D(i).
                If JOBZ = 'N', then Z is not referenced.

        LDZ     (input) INTEGER
                The leading dimension of the array Z.  LDZ >= 1, and if
                JOBZ = 'V', LDZ >= max(1,N).

        WORK    (workspace) REAL array, dimension (max(1,2*N-2))
                If JOBZ = 'N', WORK is not referenced.

        INFO    (output) INTEGER
                = 0:  successful exit
                < 0:  if INFO = -i, the i-th argument had an illegal value
                > 0:  if INFO = i, the algorithm failed to converge; i
                off-diagonal elements of E did not converge to zero.

 LAPACK driver routine (version 3.2)        April 2011                             SSTEV(3lapack)