# zlanhp (l) - Linux Manuals

## NAME

ZLANHP - 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 hermitian matrix A, supplied in packed form

## SYNOPSIS

DOUBLE PRECISION
FUNCTION ZLANHP( NORM, UPLO, N, AP, WORK )

CHARACTER NORM, UPLO

INTEGER N

DOUBLE PRECISION WORK( * )

COMPLEX*16 AP( * )

## PURPOSE

ZLANHP 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 hermitian matrix A, supplied in packed form.

## DESCRIPTION

ZLANHP returns the value

ZLANHP 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 ZLANHP as described above.
UPLO (input) CHARACTER*1
Specifies whether the upper or lower triangular part of the hermitian matrix A is supplied. = aqUaq: Upper triangular part of A is supplied
= aqLaq: Lower triangular part of A is supplied
N (input) INTEGER
The order of the matrix A. N >= 0. When N = 0, ZLANHP is set to zero.
AP (input) COMPLEX*16 array, dimension (N*(N+1)/2)
The upper or lower triangle of the hermitian matrix A, packed columnwise in a linear array. The j-th column of A is stored in the array AP as follows: if UPLO = aqUaq, AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j; if UPLO = aqLaq, AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n. Note that the imaginary parts of the diagonal elements need not be set and are assumed to be zero.
WORK (workspace) DOUBLE PRECISION array, dimension (MAX(1,LWORK)),
where LWORK >= N when NORM = aqIaq or aq1aq or aqOaq; otherwise, WORK is not referenced.