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

6       DLANGE  -  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  real
8       matrix A
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SYNOPSIS

11       DOUBLE PRECISION FUNCTION DLANGE( NORM, M, N, A, LDA, WORK )
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13           CHARACTER    NORM
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15           INTEGER      LDA, M, N
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17           DOUBLE       PRECISION A( LDA, * ), WORK( * )
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PURPOSE

20       DLANGE   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       real matrix A.
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DESCRIPTION

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

40       NORM    (input) CHARACTER*1
41               Specifies the value to  be  returned  in  DLANGE  as  described
42               above.
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44       M       (input) INTEGER
45               The  number  of  rows  of  the  matrix A.  M >= 0.  When M = 0,
46               DLANGE is set to zero.
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48       N       (input) INTEGER
49               The number of columns of the matrix A.  N >= 0.  When  N  =  0,
50               DLANGE is set to zero.
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52       A       (input) DOUBLE PRECISION array, dimension (LDA,N)
53               The m by n matrix A.
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55       LDA     (input) INTEGER
56               The leading dimension of the array A.  LDA >= max(M,1).
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58       WORK    (workspace) DOUBLE PRECISION array, dimension (MAX(1,LWORK)),
59               where LWORK >= M when NORM = 'I'; otherwise, WORK is not refer‐
60               enced.
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64 LAPACK auxiliary routine (versionNo3v.e2m)ber 2008                       DLANGE(1)