# dlanhs.f - Man Page

## Synopsis

### Functions/Subroutines

double precision function dlanhs (NORM, N, A, LDA, WORK)
DLANHS returns the value of the 1-norm, Frobenius norm, infinity-norm, or the largest absolute value of any element of an upper Hessenberg matrix.

## Function/Subroutine Documentation

### double precision function dlanhs (character NORM, integer N, double precision, dimension( lda, * ) A, integer LDA, double precision, dimension( * ) WORK)

DLANHS returns the value of the 1-norm, Frobenius norm, infinity-norm, or the largest absolute value of any element of an upper Hessenberg matrix.

Purpose:

``` DLANHS  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.```
Returns:

DLANHS

```    DLANHS = ( 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.```
Parameters:

NORM

```          NORM is CHARACTER*1
Specifies the value to be returned in DLANHS as described
above.```

N

```          N is INTEGER
The order of the matrix A.  N >= 0.  When N = 0, DLANHS is
set to zero.```

A

```          A is DOUBLE PRECISION 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

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

WORK

```          WORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK)),
where LWORK >= N when NORM = 'I'; otherwise, WORK is not
referenced.```
Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

December 2016

Definition at line 110 of file dlanhs.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page dlanhs(3) is an alias of dlanhs.f(3).

Tue Nov 14 2017 Version 3.8.0 LAPACK