LAPACK
3.4.2
LAPACK: Linear Algebra PACKage

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Functions/Subroutines  
DOUBLE PRECISION function  dlanhs (NORM, N, A, LDA, WORK) 
DLANHS returns the value of the 1norm, Frobenius norm, infinitynorm, or the largest absolute value of any element of an upper Hessenberg matrix. 
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 1norm, Frobenius norm, infinitynorm, or the largest absolute value of any element of an upper Hessenberg matrix.
Download DLANHS + dependencies [TGZ] [ZIP] [TXT]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.
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.
[in]  NORM  NORM is CHARACTER*1 Specifies the value to be returned in DLANHS as described above. 
[in]  N  N is INTEGER The order of the matrix A. N >= 0. When N = 0, DLANHS is set to zero. 
[in]  A  A is DOUBLE PRECISION array, dimension (LDA,N) The n by n upper Hessenberg matrix A; the part of A below the first subdiagonal is not referenced. 
[in]  LDA  LDA is INTEGER The leading dimension of the array A. LDA >= max(N,1). 
[out]  WORK  WORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK)), where LWORK >= N when NORM = 'I'; otherwise, WORK is not referenced. 
Definition at line 109 of file dlanhs.f.