DPOCON  -  estimate the reciprocal of the condition number
       (in the 1-norm) of  a  real  symmetric  positive  definite
       matrix  using the Cholesky factorization A = U**T*U or A =
       L*L**T computed by DPOTRF


SYNOPSIS

       SUBROUTINE DPOCON( UPLO, N, A, LDA,  ANORM,  RCOND,  WORK,
                          IWORK, INFO )

           CHARACTER      UPLO

           INTEGER        INFO, LDA, N

           DOUBLE         PRECISION ANORM, RCOND

           INTEGER        IWORK( * )

           DOUBLE         PRECISION A( LDA, * ), WORK( * )


PURPOSE

       DPOCON  estimates  the  reciprocal of the condition number
       (in the 1-norm) of  a  real  symmetric  positive  definite
       matrix  using the Cholesky factorization A = U**T*U or A =
       L*L**T computed by DPOTRF.  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
               = '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) DOUBLE PRECISION array, dimension (LDA,N)
               The triangular factor U or  L  from  the  Cholesky
               factorization  A  =  U**T*U or A = L*L**T, as com­
               puted by DPOTRF.

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

       ANORM   (input) DOUBLE PRECISION
               The  1-norm  (or  infinity-norm)  of the symmetric
               matrix A.

       RCOND   (output) DOUBLE PRECISION
               The reciprocal of  the  condition  number  of  the
               matrix  A, computed as RCOND = 1/(ANORM * AINVNM),
               where AINVNM is  an  estimate  of  the  1-norm  of


       WORK    (workspace) DOUBLE PRECISION array, dimension
               (3*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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