This manual relates to an old release of the Library.
The documentation for the current release is also available on this site.

NAG FL Interface
f06upf (zlanht)

Settings help

FL Name Style:


FL Specification Language:


1 Purpose

f06upf 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×n Hermitian tridiagonal matrix A.

2 Specification

Fortran Interface
Function f06upf ( norm, n, d, e)
Real (Kind=nag_wp) :: f06upf
Integer, Intent (In) :: n
Real (Kind=nag_wp), Intent (In) :: d(*)
Complex (Kind=nag_wp), Intent (In) :: e(*)
Character (1), Intent (In) :: norm
C Header Interface
#include <nag.h>
double  f06upf_ (const char *norm, const Integer *n, const double d[], const Complex e[], const Charlen length_norm)
The routine may be called by the names f06upf or nagf_blas_zlanht.

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.
norm='F' or 'E'
The Frobenius (or Euclidean) norm.
norm='M'
The value maxi,j|aij| (not a norm).
Constraint: norm='1', 'O', 'I', 'F', 'E' or 'M'.
2: n Integer Input
On entry: n, the order of the matrix A.
When n=0, f06upf returns zero.
Constraint: n0.
3: d(*) Real (Kind=nag_wp) array Input
Note: the dimension of the array d must be at least max(1,n) .
On entry: the n diagonal elements of the tridiagonal matrix A.
4: e(*) Complex (Kind=nag_wp) array Input
Note: the dimension of the array e must be at least max(1,n-1) .
On entry: the (n-1) subdiagonal or superdiagonal elements of the tridiagonal matrix A.

6 Error Indicators and Warnings

None.

7 Accuracy

Not applicable.

8 Parallelism and Performance

f06upf is not threaded in any implementation.

9 Further Comments

None.

10 Example

None.