Provided by: liblapack-doc_3.3.1-1_all

#### NAME

```       LAPACK-3 - returns the value of the one norm, or the Frobenius norm, or the infinity norm,
or the element of largest absolute value of a Hessenberg matrix A

```

#### SYNOPSIS

```       REAL FUNCTION CLANHS( NORM, N, A, LDA, WORK )

CHARACTER NORM

INTEGER   LDA, N

REAL      WORK( * )

COMPLEX   A( LDA, * )

```

#### PURPOSE

```       CLANHS  returns the value of the one norm,  or the Frobenius norm, or the  infinity  norm,
or the  element of  largest absolute value  of a Hessenberg matrix A.

```

#### DESCRIPTION

```        CLANHS returns the value
CLANHS = ( max(abs(A(i,j))), NORM = 'M' or 'm'
(
( norm1(A),         NORM = '1', 'O' or 'o'
(
( normI(A),         NORM = 'I' or 'i'
(
( normF(A),         NORM = 'F', 'f', 'E' or 'e'
where  norm1  denotes the  one norm of a matrix (maximum column sum),
normI  denotes the  infinity norm  of a matrix  (maximum row sum) and
normF  denotes the  Frobenius norm of a matrix (square root of sum of
squares).  Note that  max(abs(A(i,j)))  is not a consistent matrix norm.

```

#### ARGUMENTS

```        NORM    (input) CHARACTER*1
Specifies the value to be returned in CLANHS as described
above.

N       (input) INTEGER
The order of the matrix A.  N >= 0.  When N = 0, CLANHS is
set to zero.

A       (input) COMPLEX array, dimension (LDA,N)
The n by n upper Hessenberg matrix A; the part of A below the
first sub-diagonal is not referenced.

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

WORK    (workspace) REAL array, dimension (MAX(1,LWORK)),
where LWORK >= N when NORM = 'I'; otherwise, WORK is not
referenced.

LAPACK auxiliary routine (version 3.2)     April 2011                            CLANHS(3lapack)
```