DSPCON  -  estimate the reciprocal of the condition number
       (in the 1-norm) of a real symmetric packed matrix A  using
       the factorization A = U*D*U**T or A = L*D*L**T computed by
       DSPTRF


SYNOPSIS

       SUBROUTINE DSPCON( UPLO, N, AP, IPIV, ANORM, RCOND,  WORK,
                          IWORK, INFO )

           CHARACTER      UPLO

           INTEGER        INFO, N

           DOUBLE         PRECISION ANORM, RCOND

           INTEGER        IPIV( * ), IWORK( * )

           DOUBLE         PRECISION AP( * ), WORK( * )


PURPOSE

       DSPCON  estimates  the  reciprocal of the condition number
       (in the 1-norm) of a real symmetric packed matrix A  using
       the factorization A = U*D*U**T or A = L*D*L**T computed by
       DSPTRF.  An estimate is obtained for norm(inv(A)), and the
       reciprocal  of the condition number is computed as RCOND =
       1 / (ANORM * norm(inv(A))).


ARGUMENTS

       UPLO    (input) CHARACTER*1
               Specifies whether the details of the factorization
               are stored as an upper or lower triangular matrix.
               = 'U':  Upper triangular, form is A = U*D*U**T;
               = 'L':  Lower triangular, form is A = L*D*L**T.

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

       AP      (input) DOUBLE PRECISION array, dimension
               (N*(N+1)/2)
               The  block  diagonal  matrix D and the multipliers
               used to obtain the factor U or L  as  computed  by
               DSPTRF, stored as a packed triangular matrix.

       IPIV    (input) INTEGER array, dimension (N)
               Details  of  the interchanges and the block struc­
               ture of D as determined by DSPTRF.

       ANORM   (input) DOUBLE PRECISION
               The 1-norm of the original matrix A.

       RCOND   (output) DOUBLE PRECISION
               The reciprocal of  the  condition  number  of  the

               where AINVNM is  an  estimate  of  the  1-norm  of
               inv(A) computed in this routine.

       WORK    (workspace) DOUBLE PRECISION array, dimension
               (2*N)

       IWORK    (workspace) INTEGER array, dimension (N)

       INFO    (output) INTEGER
               = 0:  successful exit
               < 0:  if INFO = -i, the i-th argument had an ille­
               gal value


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