---
name: "zlanhe"
section: "3"
platform: "linux"
package: "lapack-doc"
version: "3.12.1-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/zlanhe.f"
---

# zlanhe(3)

Part of [zlanhe.f(3)](/zlanhe.f/3.md).

## NAME

SRC/zlanhe.f

## SYNOPSIS

### Functions/Subroutines

double precision function **zlanhe** (norm, uplo, n, a, lda, work)\
 **ZLANHE** returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a complex Hermitian matrix.

## Function/Subroutine Documentation

### double precision function zlanhe (character norm, character uplo, integer n, complex\*16, dimension( lda, \* ) a, integer lda, double precision, dimension( \* ) work)

**ZLANHE** returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a complex Hermitian matrix.

**Purpose:**

```
!>
!> ZLANHE  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.
!>
```

**Returns**

ZLANHE

```
!>
!>    ZLANHE = ( 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 ZLANHE as described
!>          above.
!>
```

*UPLO*

```
!>          UPLO is CHARACTER*1
!>          Specifies whether the upper or lower triangular part of the
!>          hermitian 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, ZLANHE is
!>          set to zero.
!>
```

*A*

```
!>          A is COMPLEX*16 array, dimension (LDA,N)
!>          The hermitian 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. Note that the imaginary parts of the diagonal
!>          elements need not be set and are assumed to be zero.
!>
```

*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.

Definition at line **123** of file **zlanhe.f**.

## Author

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