1CLANHS(1)           LAPACK auxiliary routine (version 3.2)           CLANHS(1)
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NAME

6       CLANHS  -  returns the value of the one norm, or the Frobenius norm, or
7       the infinity norm, or the element of largest absolute value of  a  Hes‐
8       senberg matrix A
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SYNOPSIS

11       REAL FUNCTION CLANHS( NORM, N, A, LDA, WORK )
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13           CHARACTER NORM
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15           INTEGER   LDA, N
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17           REAL      WORK( * )
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19           COMPLEX   A( LDA, * )
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PURPOSE

22       CLANHS   returns  the value of the one norm,  or the Frobenius norm, or
23       the  infinity norm,  or the  element of  largest absolute value   of  a
24       Hessenberg matrix A.
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DESCRIPTION

27       CLANHS returns the value
28          CLANHS = ( max(abs(A(i,j))), NORM = 'M' or 'm'
29                   (
30                   ( norm1(A),         NORM = '1', 'O' or 'o'
31                   (
32                   ( normI(A),         NORM = 'I' or 'i'
33                   (
34                   (  normF(A),          NORM  =  'F',  'f',  'E' or 'e' where
35       norm1  denotes the  one norm of a matrix (maximum  column  sum),  normI
36       denotes  the   infinity  norm  of a matrix  (maximum row sum) and normF
37       denotes the  Frobenius  norm  of  a  matrix  (square  root  of  sum  of
38       squares).   Note  that   max(abs(A(i,j)))   is  not a consistent matrix
39       norm.
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ARGUMENTS

42       NORM    (input) CHARACTER*1
43               Specifies the value to  be  returned  in  CLANHS  as  described
44               above.
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46       N       (input) INTEGER
47               The  order of the matrix A.  N >= 0.  When N = 0, CLANHS is set
48               to zero.
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50       A       (input) COMPLEX array, dimension (LDA,N)
51               The n by n upper Hessenberg matrix A; the part of A  below  the
52               first sub-diagonal is not referenced.
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54       LDA     (input) INTEGER
55               The leading dimension of the array A.  LDA >= max(N,1).
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57       WORK    (workspace) REAL array, dimension (MAX(1,LWORK)),
58               where LWORK >= N when NORM = 'I'; otherwise, WORK is not refer‐
59               enced.
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63 LAPACK auxiliary routine (versionNo3v.e2m)ber 2008                       CLANHS(1)