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

NAME

       LAPACK-3  - computes all the eigenvalues and, optionally, eigenvectors of a real symmetric
       matrix A in packed storage

SYNOPSIS

       SUBROUTINE SSPEV( JOBZ, UPLO, N, AP, W, Z, LDZ, WORK, INFO )

           CHARACTER     JOBZ, UPLO

           INTEGER       INFO, LDZ, N

           REAL          AP( * ), W( * ), WORK( * ), Z( LDZ, * )

PURPOSE

       SSPEV computes all the eigenvalues and,  optionally,  eigenvectors  of  a  real  symmetric
       matrix A in packed storage.

ARGUMENTS

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

        UPLO    (input) CHARACTER*1
                = 'U':  Upper triangle of A is stored;
                = 'L':  Lower triangle of A is stored.

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

        AP      (input/output) REAL array, dimension (N*(N+1)/2)
                On entry, the upper or lower triangle of the symmetric matrix
                A, packed columnwise in a linear array.  The j-th column of A
                is stored in the array AP as follows:
                if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
                if UPLO = 'L', AP(i + (j-1)*(2*n-j)/2) = A(i,j) for j<=i<=n.
                On exit, AP is overwritten by values generated during the
                reduction to tridiagonal form.  If UPLO = 'U', the diagonal
                and first superdiagonal of the tridiagonal matrix T overwrite
                the corresponding elements of A, and if UPLO = 'L', the
                diagonal and first subdiagonal of T overwrite the
                corresponding elements of A.

        W       (output) REAL array, dimension (N)
                If INFO = 0, the eigenvalues in ascending order.

        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 W(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 (3*N)

        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 an intermediate tridiagonal
                form did not converge to zero.

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