1SLANHS(1)           LAPACK auxiliary routine (version 3.1)           SLANHS(1)
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NAME

6       SLANHS  -  the  value  of  the  one norm, or the Frobenius norm, or the
7       infinity norm, or the element of largest absolute value of a Hessenberg
8       matrix A
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SYNOPSIS

11       REAL FUNCTION SLANHS( 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      A( LDA, * ), WORK( * )
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PURPOSE

20       SLANHS   returns  the value of the one norm,  or the Frobenius norm, or
21       the  infinity norm,  or the  element of  largest absolute value   of  a
22       Hessenberg matrix A.
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DESCRIPTION

26       SLANHS returns the value
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28          SLANHS = ( 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'
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36       where   norm1   denotes the  one norm of a matrix (maximum column sum),
37       normI  denotes the  infinity norm  of a matrix  (maximum row  sum)  and
38       normF   denotes  the  Frobenius norm of a matrix (square root of sum of
39       squares).  Note that  max(abs(A(i,j)))   is  not  a  consistent  matrix
40       norm.
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ARGUMENTS

44       NORM    (input) CHARACTER*1
45               Specifies  the  value  to  be  returned  in SLANHS as described
46               above.
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48       N       (input) INTEGER
49               The order of the matrix A.  N >= 0.  When N = 0, SLANHS is  set
50               to zero.
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52       A       (input) REAL array, dimension (LDA,N)
53               The  n  by n upper Hessenberg matrix A; the part of A below the
54               first sub-diagonal is not referenced.
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56       LDA     (input) INTEGER
57               The leading dimension of the array A.  LDA >= max(N,1).
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59       WORK    (workspace) REAL array, dimension (MAX(1,LWORK)),
60               where LWORK >= N when NORM = 'I'; otherwise, WORK is not refer‐
61               enced.
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65 LAPACK auxiliary routine (versionNo3v.e1m)ber 2006                       SLANHS(1)
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