Provided by: liblapack-doc_3.3.1-1_all

#### NAME

```       LAPACK-3  -  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 ZPOTRF

```

#### SYNOPSIS

```       SUBROUTINE ZPOCON( UPLO, N, A, LDA, ANORM, RCOND, WORK, RWORK, INFO )

CHARACTER      UPLO

INTEGER        INFO, LDA, N

DOUBLE         PRECISION ANORM, RCOND

DOUBLE         PRECISION RWORK( * )

COMPLEX*16     A( LDA, * ), WORK( * )

```

#### PURPOSE

```       ZPOCON  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 ZPOTRF.
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) COMPLEX*16 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 ZPOTRF.

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 Hermitian 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) COMPLEX*16 array, dimension (2*N)

RWORK   (workspace) DOUBLE PRECISION array, dimension (N)

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

LAPACK routine (version 3.3.1)             April 2011                            ZPOCON(3lapack)
```