NAG Library Routine Document

F06FTF

1  Purpose

2  Specification

3  Description

4  References

5  Parameters

1:     N – INTEGERInput

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

2:     DELTA – REAL (KIND=nag_wp)Input/Output

On entry: the original scalar $\delta$.

On exit: the transformed scalar $\delta$.

3:     Y($*$) – REAL (KIND=nag_wp) arrayInput/Output

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

On entry: the original vector $y$.

If $\mathbf{INCY}>0$, $y_{\mathit{i}}$ must be stored in $\mathbf{Y}\left(1+\left(\mathit{i}-1\right)\times \mathbf{INCY}\right)$, for $\mathit{i}=1,2,\dots ,\mathbf{N}$.

If $\mathbf{INCY}<0$, $y_{\mathit{i}}$ must be stored in $\mathbf{Y}\left(1-\left(\mathbf{N}-\mathit{i}\right)\times \mathbf{INCY}\right)$, for $\mathit{i}=1,2,\dots ,\mathbf{N}$.

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

4:     INCY – INTEGERInput

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

5:     ZETA – REAL (KIND=nag_wp)Input

On entry: the scalar $\zeta$, as returned by F06FRF.

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

Constraint: if $\mathbf{ZETA}=0.0$, $\mathbf{N}=0$.

6:     Z($*$) – 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 F06FRF.

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 $\mathit{i}=1,2,\dots ,\mathbf{N}$.

7:     INCZ – INTEGERInput

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

6  Error Indicators and Warnings

7  Accuracy

8  Further Comments

9  Example