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man pages->IRIX man pages -> complib/cppcon (3)
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### Contents

```
CPPCON(3F)							    CPPCON(3F)

```

### NAME[Toc][Back]

```     CPPCON - estimate the reciprocal of the condition number (in the 1-norm)
of	a complex Hermitian positive definite packed matrix using the Cholesky
factorization A = U**H*U or A = L*L**H computed by	CPPTRF
```

### SYNOPSIS[Toc][Back]

```     SUBROUTINE	CPPCON(	UPLO, N, AP, ANORM, RCOND, WORK, RWORK,	INFO )

CHARACTER	UPLO

INTEGER	INFO, N

REAL		ANORM, RCOND

REAL		RWORK( * )

COMPLEX	AP( * ), WORK( * )
```

### PURPOSE[Toc][Back]

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

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[Toc][Back]

```     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.

AP	     (input) COMPLEX array, dimension (N*(N+1)/2)
The triangular factor U or	L from the Cholesky factorization A =
U**H*U or A = L*L**H, packed columnwise in	a linear array.	 The
j-th column of U or L is stored in	the array AP as	follows:  if
UPLO = 'U', AP(i +	(j-1)*j/2) = U(i,j) for	1<=i<=j; if UPLO =
'L', AP(i + (j-1)*(2n-j)/2) = L(i,j) for j<=i<=n.

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

RCOND   (output) 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.

Page 1

CPPCON(3F)							    CPPCON(3F)

WORK    (workspace) COMPLEX array,	dimension (2*N)

RWORK   (workspace) REAL array, dimension (N)

INFO    (output) INTEGER
= 0:  successful exit
< 0:  if INFO = -i, the i-th argument had an illegal value
CPPCON(3F)							    CPPCON(3F)

```

### NAME[Toc][Back]

```     CPPCON - estimate the reciprocal of the condition number (in the 1-norm)
of	a complex Hermitian positive definite packed matrix using the Cholesky
factorization A = U**H*U or A = L*L**H computed by	CPPTRF
```

### SYNOPSIS[Toc][Back]

```     SUBROUTINE	CPPCON(	UPLO, N, AP, ANORM, RCOND, WORK, RWORK,	INFO )

CHARACTER	UPLO

INTEGER	INFO, N

REAL		ANORM, RCOND

REAL		RWORK( * )

COMPLEX	AP( * ), WORK( * )
```

### PURPOSE[Toc][Back]

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

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[Toc][Back]

```     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.

AP	     (input) COMPLEX array, dimension (N*(N+1)/2)
The triangular factor U or	L from the Cholesky factorization A =
U**H*U or A = L*L**H, packed columnwise in	a linear array.	 The
j-th column of U or L is stored in	the array AP as	follows:  if
UPLO = 'U', AP(i +	(j-1)*j/2) = U(i,j) for	1<=i<=j; if UPLO =
'L', AP(i + (j-1)*(2n-j)/2) = L(i,j) for j<=i<=n.

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

RCOND   (output) 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.

Page 1

CPPCON(3F)							    CPPCON(3F)

WORK    (workspace) COMPLEX array,	dimension (2*N)

RWORK   (workspace) REAL array, dimension (N)

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

PPPPaaaaggggeeee 2222```
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