NAG Library Routine Document

f06fuf (dlhous)

1

Purpose

2

Specification

3

Description

4

References

5

Arguments

1:     $\mathbf{n}$ – IntegerInput

On entry: $n$, the number of elements in $x$ and $z$.

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

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

On entry: the vector $z$, as returned by f06fsf.

If $\mathbf{incz}>0$, $z_{\mathit{i}}$ must be stored in $\mathbf{z}\left(1+\left(\mathit{i}-1\right)\times \mathbf{incz}\right)$, for $\mathit{i}=1,2,\dots ,\mathbf{n}$.

If $\mathbf{incz}<0$, $z_{\mathit{i}}$ must be stored in $\mathbf{z}\left(1-\left(\mathbf{n}-\mathit{i}\right)\times \mathbf{incz}\right)$, for $\mathit{i}=1,2,\dots ,\mathbf{n}$.

3:     $\mathbf{incz}$ – IntegerInput

On entry: the increment in the subscripts of z between successive elements of $z$.

4:     $\mathbf{z1}$ – Real (Kind=nag_wp)Input

On entry: the scalar $\zeta$, as returned by f06fsf.

If $\zeta =0$, $P$ is assumed to be the unit matrix and the transformation is skipped.

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

On entry: the original scalar $\alpha$.

On exit: the transformed scalar $\alpha$.

6:     $\mathbf{x}\left(*\right)$ – Real (Kind=nag_wp) arrayInput/Output

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

On entry: the original vector $x$.

If $\mathbf{incx}>0$, $x_{\mathit{i}}$ must be stored in $\mathbf{x}\left(1+\left(\mathit{i}-1\right)\times \mathbf{incx}\right)$, for $\mathit{i}=1,2,\dots ,\mathbf{n}$.

If $\mathbf{incx}<0$, $x_{\mathit{i}}$ must be stored in $\mathbf{x}\left(1-\left(\mathbf{n}-\mathit{i}\right)\times \mathbf{incx}\right)$, for $\mathit{i}=1,2,\dots ,\mathbf{n}$.

On exit: the transformed vector $x$ stored in the same array elements used to supply the original vector $x$.

7:     $\mathbf{incx}$ – IntegerInput

On entry: the increment in the subscripts of x between successive elements of $x$.

6

Error Indicators and Warnings

7

Accuracy

8

Parallelism and Performance

9

Further Comments

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Example