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NAME
     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( * )



     #include <sunperf.h>

     void dpocon(char uplo, int n, double *da,  int  lda,  double
               anorm, double *drcond, int *info) ;

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
               inv(A) computed in this routine.

     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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