NAG Library Routine Document

f06ucf (zlanhe)

1
Purpose

f06ucf returns, via the function name, the value of the 1-norm, the -norm, the Frobenius norm, or the maximum absolute value of the elements of a complex n by n Hermitian matrix.

2
Specification

Fortran Interface
Function f06ucf ( norm, uplo, n, a, lda, work)
Real (Kind=nag_wp):: f06ucf
Integer, Intent (In):: n, lda
Real (Kind=nag_wp), Intent (Inout):: work(*)
Complex (Kind=nag_wp), Intent (In):: a(lda,*)
Character (1), Intent (In):: norm, uplo
C Header Interface
#include <nagmk26.h>
double  f06ucf_ (const char *norm, const char *uplo, const Integer *n, const Complex a[], const Integer *lda, double work[], const Charlen length_norm, const Charlen length_uplo)

3
Description

None.

4
References

None.

5
Arguments

1:     norm – Character(1)Input
On entry: specifies the value to be returned.
norm='1' or 'O'
The 1-norm.
norm='I'
The -norm (= the 1-norm for a Hermitian matrix).
norm='F' or 'E'
The Frobenius (or Euclidean) norm.
norm='M'
The value maxi,jaij (not a norm).
Constraint: norm='1', 'O', 'I', 'F', 'E' or 'M'.
2:     uplo – Character(1)Input
On entry: specifies whether the upper or lower triangular part of A is stored.
uplo='U'
The upper triangular part of A is stored.
uplo='L'
The lower triangular part of A is stored.
Constraint: uplo='U' or 'L'.
3:     n – IntegerInput
On entry: n, the order of the matrix A.
When n=0, f06ucf returns zero.
Constraint: n0.
4:     alda* – Complex (Kind=nag_wp) arrayInput
Note: the second dimension of the array a must be at least max1,n.
On entry: the n by n Hermitian matrix A.
  • If uplo='U', the upper triangular part of A must be stored and the elements of the array below the diagonal are not referenced.
  • If uplo='L', the lower triangular part of A must be stored and the elements of the array above the diagonal are not referenced.
5:     lda – IntegerInput
On entry: the first dimension of the array a as declared in the (sub)program from which f06ucf is called.
Constraint: lda max1,n .
6:     work* – Real (Kind=nag_wp) arrayWorkspace
Note: the dimension of the array work must be at least max1,n  if norm='1', 'O' or 'I', and at least 1 otherwise.

6
Error Indicators and Warnings

None.

7
Accuracy

Not applicable.

8
Parallelism and Performance

f06ucf is not threaded in any implementation.

9
Further Comments

None.

10
Example

None.