slanhs()

real function slanhs	(	character	norm,
		integer	n,
		real, dimension( lda, * )	a,
		integer	lda,
		real, dimension( * )	work )

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

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Purpose:

!>
!> SLANHS  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

SLANHS

!>
!>    SLANHS = ( 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

[in]	NORM	!> NORM is CHARACTER*1 !> Specifies the value to be returned in SLANHS as described !> above. !>
[in]	N	!> N is INTEGER !> The order of the matrix A. N >= 0. When N = 0, SLANHS is !> set to zero. !>
[in]	A	!> A is REAL array, dimension (LDA,N) !> The n by n upper Hessenberg matrix A; the part of A below the !> first sub-diagonal is not referenced. !>
[in]	LDA	!> LDA is INTEGER !> The leading dimension of the array A. LDA >= max(N,1). !>
[out]	WORK	!> WORK is REAL 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.