CPOCON(3)      LAPACK routine of NEC Numeric Library Collection      CPOCON(3)



NAME
       CPOCON

SYNOPSIS
       SUBROUTINE CPOCON (UPLO, N, A, LDA, ANORM, RCOND, WORK, RWORK, INFO)



PURPOSE
            CPOCON estimates the reciprocal of the condition number (in the
            1-norm) of a complex Hermitian positive definite matrix using the
            Cholesky factorization A = U**H*U or A = L*L**H computed by CPOTRF.

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

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

           A         (input)
                     A is COMPLEX array, dimension (LDA,N)
                     The triangular factor U or L from the Cholesky factorization
                     A = U**H*U or A = L*L**H, as computed by CPOTRF.

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

           ANORM     (input)
                     ANORM is REAL
                     The 1-norm (or infinity-norm) of the Hermitian matrix A.

           RCOND     (output)
                     RCOND is REAL
                     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      (output)
                     WORK is COMPLEX array, dimension (2*N)

           RWORK     (output)
                     RWORK is REAL array, dimension (N)

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



LAPACK routine                  31 October 2017                      CPOCON(3)