NAG Library Routine Document

f06bef (drotj)

1

Purpose

2

Specification

3

Description

4

References

5

Arguments

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

On entry: specifies the property which determines the precise form of the rotation.

$\mathbf{job}=\text{'B'}$

$c\ge 1/\sqrt{2}$.

$\mathbf{job}=\text{'S'}$

$0\le c\le 1/\sqrt{2}$.

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

$\left|a\right|\ge \left|b\right|$.

Constraint: $\mathbf{job}=\text{'B'}$, $\text{'S'}$ or $\text{'M'}$.

2:     $\mathbf{x}$ – Real (Kind=nag_wp)Input/Output

On entry: the value $x$, the $\left(1,1\right)$ element of the input matrix.

On exit: the value $a$.

3:     $\mathbf{y}$ – Real (Kind=nag_wp)Input/Output

On entry: the value $y$, the $\left(1,2\right)$ or $\left(2,1\right)$ element of the input matrix.

On exit: the value $t$, the tangent of the rotation.

4:     $\mathbf{z}$ – Real (Kind=nag_wp)Input/Output

On entry: the value $z$. the $\left(2,2\right)$ element of the input matrix.

On exit: the value $b$.

5:     $\mathbf{c}$ – Real (Kind=nag_wp)Output

On exit: the value $c$, the cosine of the rotation.

6:     $\mathbf{s}$ – Real (Kind=nag_wp)Output

On exit: the value $s$, the sine of the rotation.

6

Error Indicators and Warnings

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Accuracy

8

Parallelism and Performance

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Further Comments

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Example