# clansy (l) - Linux Man Pages

## NAME

CLANSY - returns the value of the one norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a complex symmetric matrix A

## SYNOPSIS

REAL FUNCTION
CLANSY( NORM, UPLO, N, A, LDA, WORK )

CHARACTER NORM, UPLO

INTEGER LDA, N

REAL WORK( * )

COMPLEX A( LDA, * )

## PURPOSE

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

## DESCRIPTION

CLANSY returns the value

CLANSY max(abs(A(i,j))), NORM aqMaq or aqmaq

(

norm1(A),         NORM aq1aq, aqOaq or aqoaq

(

normI(A),         NORM aqIaq or aqiaq

(

normF(A),         NORM aqFaq, aqfaq, aqEaq or aqeaq 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.

## ARGUMENTS

NORM (input) CHARACTER*1
Specifies the value to be returned in CLANSY as described above.
UPLO (input) CHARACTER*1
Specifies whether the upper or lower triangular part of the symmetric matrix A is to be referenced. = aqUaq: Upper triangular part of A is referenced
= aqLaq: Lower triangular part of A is referenced
N (input) INTEGER
The order of the matrix A. N >= 0. When N = 0, CLANSY is set to zero.
A (input) COMPLEX array, dimension (LDA,N)
The symmetric matrix A. If UPLO = aqUaq, 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 = aqLaq, 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 (input) INTEGER
The leading dimension of the array A. LDA >= max(N,1).
WORK (workspace) REAL array, dimension (MAX(1,LWORK)),
where LWORK >= N when NORM = aqIaq or aq1aq or aqOaq; otherwise, WORK is not referenced.