NAG Library Routine Document

F06BEF

1  Purpose

2  Specification

3  Description

4  References

5  Parameters

1:     $\mathrm{JOB}$ – 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:     $\mathrm{X}$ – 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:     $\mathrm{Y}$ – 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:     $\mathrm{Z}$ – 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:     $\mathrm{C}$ – REAL (KIND=nag_wp)Output

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

6:     $\mathrm{S}$ – REAL (KIND=nag_wp)Output

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

6  Error Indicators and Warnings

7  Accuracy

8  Parallelism and Performance

9  Further Comments

10  Example