NAG Library Routine Document

f06upf (zlanht)

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Purpose

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Specification

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Description

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References

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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:     $\mathbf{n}$ – IntegerInput

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

When $\mathbf{n}=0$, f06upf returns zero.

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

3:     $\mathbf{d}\left(*\right)$ – Real (Kind=nag_wp) arrayInput

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

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

4:     $\mathbf{e}\left(*\right)$ – Complex (Kind=nag_wp) arrayInput

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

On entry: the ($n-1$) subdiagonal or superdiagonal elements of the tridiagonal matrix $A$.

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Error Indicators and Warnings

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Accuracy

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Parallelism and Performance

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Further Comments

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Example