NAME

       dlansy.f -

SYNOPSIS

   Functions/Subroutines
       double precision function dlansy (NORM, UPLO, N, A, LDA, WORK)
           DLANSY returns the value of the 1-norm, or the Frobenius norm, or the infinity norm,
           or the element of largest absolute value of a real symmetric matrix.

Function/Subroutine Documentation

   double precision function dlansy (characterNORM, characterUPLO, integerN, double precision,
       dimension( lda, * )A, integerLDA, double precision, dimension( * )WORK)
       DLANSY returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or
       the element of largest absolute value of a real symmetric matrix.

       Purpose:

            DLANSY  returns the value of the one norm,  or the Frobenius norm, or
            the  infinity norm,  or the  element of  largest absolute value  of a
            real symmetric matrix A.

       Returns:
           DLANSY

               DLANSY = ( 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.

       Parameters:
           NORM

                     NORM is CHARACTER*1
                     Specifies the value to be returned in DLANSY as described
                     above.

           UPLO

                     UPLO is CHARACTER*1
                     Specifies whether the upper or lower triangular part of the
                     symmetric matrix A is to be referenced.
                     = 'U':  Upper triangular part of A is referenced
                     = 'L':  Lower triangular part of A is referenced

           N

                     N is INTEGER
                     The order of the matrix A.  N >= 0.  When N = 0, DLANSY is
                     set to zero.

           A

                     A is DOUBLE PRECISION array, dimension (LDA,N)
                     The symmetric matrix A.  If UPLO = 'U', the leading n by n
                     upper triangular part of A contains the upper triangular part
                     of the matrix A, and the strictly lower triangular part of A
                     is not referenced.  If UPLO = 'L', the leading n by n lower
                     triangular part of A contains the lower triangular part of
                     the matrix A, and the strictly upper triangular part of A is
                     not referenced.

           LDA

                     LDA is INTEGER
                     The leading dimension of the array A.  LDA >= max(N,1).

           WORK

                     WORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK)),
                     where LWORK >= N when NORM = 'I' or '1' or 'O'; otherwise,
                     WORK is not referenced.

       Author:
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Date:
           September 2012

       Definition at line 123 of file dlansy.f.

Author

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