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

6       DLANSY  -  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       symmetric matrix A
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SYNOPSIS

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

20       DLANSY   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 symmetric matrix A.
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DESCRIPTION

25       DLANSY returns the value
26          DLANSY = ( 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  DLANSY  as  described
42               above.
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44       UPLO    (input) CHARACTER*1
45               Specifies  whether  the  upper  or lower triangular part of the
46               symmetric matrix A is to be referenced.  = 'U':  Upper triangu‐
47               lar part of A is referenced
48               = 'L':  Lower triangular part of A is referenced
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50       N       (input) INTEGER
51               The  order of the matrix A.  N >= 0.  When N = 0, DLANSY is set
52               to zero.
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54       A       (input) DOUBLE PRECISION array, dimension (LDA,N)
55               The symmetric matrix A.  If UPLO = 'U',  the  leading  n  by  n
56               upper  triangular  part of A contains the upper triangular part
57               of the matrix A, and the strictly lower triangular part of A is
58               not referenced.  If UPLO = 'L', the leading n by n lower trian‐
59               gular part of A contains  the  lower  triangular  part  of  the
60               matrix  A,  and  the strictly upper triangular part of A is not
61               referenced.
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63       LDA     (input) INTEGER
64               The leading dimension of the array A.  LDA >= max(N,1).
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66       WORK    (workspace) DOUBLE PRECISION array, dimension (MAX(1,LWORK)),
67               where LWORK >= N when NORM = 'I' or '1' or 'O'; otherwise, WORK
68               is not referenced.
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72 LAPACK auxiliary routine (versionNo3v.e2m)ber 2008                       DLANSY(1)
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