NAG FL Interface
f06rnf (dlangt)

1 Purpose

2 Specification

3 Description

4 References

5 Arguments

1: $\mathbf{norm}$ – Character(1) Input

On entry: specifies the value to be returned.

$\mathbf{norm}=\text{'1'}$ or $\text{'O'}$

The $1$-norm.

$\mathbf{norm}=\text{'I'}$

The $\infty$-norm.

$\mathbf{norm}=\text{'F'}$ or $\text{'E'}$

The Frobenius (or Euclidean) norm.

$\mathbf{norm}=\text{'M'}$

The value ${\displaystyle \underset{i,j}{\max }}\left|a_{ij}\right|$ (not a norm).

Constraint: $\mathbf{norm}=\text{'1'}$, $\text{'O'}$, $\text{'I'}$, $\text{'F'}$, $\text{'E'}$ or $\text{'M'}$.

2: $\mathbf{n}$ – Integer Input

On entry: $n$, the order of the matrix $A$.

When $\mathbf{n}=0$, f06rnf returns zero.

Constraint: $\mathbf{n}\ge 0$.

3: $\mathbf{dl}\left(*\right)$ – Real (Kind=nag_wp) array Input

Note: the dimension of the array dl must be at least $\max \left(1,\mathbf{n}-1\right)$.

On entry: the ($n-1$) subdiagonal elements of $A$.

4: $\mathbf{d}\left(*\right)$ – Real (Kind=nag_wp) array Input

Note: the dimension of the array d must be at least $\max \left(1,\mathbf{n}\right)$.

On entry: the $n$ diagonal elements of $A$.

5: $\mathbf{du}\left(*\right)$ – Real (Kind=nag_wp) array Input

Note: the dimension of the array du must be at least $\max \left(1,\mathbf{n}-1\right)$.

On entry: the ($n-1$) superdiagonal elements of $A$.

6 Error Indicators and Warnings

7 Accuracy

8 Parallelism and Performance

9 Further Comments

10 Example