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[Lapack] lapack help

sir/Madam,
    I want to use a routine from lapack


          SSYEV( JOBZ, UPLO, N, A, LDA, W, WORK, LWORK, INFO )

           CHARACTER     JOBZ, UPLO

           INTEGER       INFO, LDA, LWORK, N

           REAL          A( LDA, * ), W( * ), WORK( * )

PURPOSE
       SSYEV computes all eigenvalues and, optionally, eigenvectors of a
real
       symmetric matrix A.


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.

       A       (input/output) REAL array, dimension (LDA, N)
               On  entry,  the symmetric matrix A.  If UPLO = 'U', the
 leading N-by-N upper triangular part of A contains the
upper triangular
               part  of the matrix A.  If UPLO = 'L', the leading N-by-N
lower
               triangular part of A contains the lower triangular part of
the
               matrix A.  On exit, if JOBZ = 'V', then if INFO = 0, A
contains
               the orthonormal eigenvectors of the matrix A.  If JOBZ  =
'N',
               then on exit the lower triangle (if UPLO='L') or the upper
tri-
               angle (if UPLO='U') of A, including the diagonal, is
destroyed.

       LDA     (input) INTEGER
               The leading dimension of the array A.  LDA >= max(1,N).

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

       WORK    (workspace/output) REAL array, dimension (MAX(1,LWORK))
               On exit, if INFO = 0, WORK(1) returns the optimal LWORK.

       LWORK   (input) INTEGER
               The  length  of  the  array  WORK.  LWORK >= max(1,3*N-1).
For
               optimal efficiency, LWORK >= (NB+2)*N, where NB is  the
block-
               size for SSYTRD returned by ILAENV.

               If  LWORK  = -1, then a workspace query is assumed; the
routine
               only calculates the optimal size of  the  WORK  array,
returns
               this  value  as the first entry of the WORK array, and no
error
               message related to LWORK is issued by XERBLA.

       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 3November 2006
SSYEV(3)



*here I do not understand LDA, WORK and LWORK. how to know what will be
LWORK and LDA.
*



with best regards
RAVINDRA PANKAJ
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