DLANSY (3)  Linux Manuals
NAME
dlansy.f 
SYNOPSIS
Functions/Subroutines
DOUBLE PRECISION function dlansy (NORM, UPLO, N, A, LDA, WORK)
DLANSY returns the value of the 1norm, 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 1norm, 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.
UPLOUPLO 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
NN is INTEGER The order of the matrix A. N >= 0. When N = 0, DLANSY is set to zero.
AA 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.
LDALDA is INTEGER The leading dimension of the array A. LDA >= max(N,1).
WORKWORK 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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