NAG FL Interface
f06qqf (dutupd)

1 Purpose

2 Specification

3 Description

4 References

5 Arguments

1: $\mathbf{n}$ – Integer Input

On entry: $n$, the order of the matrices $U$ and $R$.

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

2: $\mathbf{alpha}$ – Real (Kind=nag_wp) Input

On entry: the scalar $\alpha$.

3: $\mathbf{x}\left(*\right)$ – Real (Kind=nag_wp) array Input/Output

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

On entry: the vector $x$. $x_{\mathit{i}}$ must be stored in $\mathbf{x}\left(1+(\mathit{i}–1)\times \mathbf{incx}\right)$, for $\mathit{i}=1,2,\dots ,\mathbf{n}$.

On exit: the referenced elements are overwritten by the tangents of the rotations $Q_{\mathit{k}}$, for $\mathit{k}=1,2,\dots ,n$.

4: $\mathbf{incx}$ – Integer Input

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

Constraint: $\mathbf{incx}>0$.

5: $\mathbf{a}(\mathbf{lda},*)$ – Real (Kind=nag_wp) array Input/Output

Note: the second dimension of the array a must be at least $\mathbf{n}$.

On entry: the $n\times n$ upper triangular matrix $U$.

On exit: the upper triangular matrix $R$.

6: $\mathbf{lda}$ – Integer Input

On entry: the first dimension of the array a as declared in the (sub)program from which f06qqf is called.

Constraint: $\mathbf{lda}\ge \max (1,\mathbf{n})$.

7: $\mathbf{c}\left(\mathbf{n}\right)$ – Real (Kind=nag_wp) array Output

On exit: the values $c_{\mathit{k}}$, the cosines of the rotations $Q_{\mathit{k}}$, for $\mathit{k}=1,2,\dots ,n$.

8: $\mathbf{s}\left(\mathbf{n}\right)$ – Real (Kind=nag_wp) array Output

On exit: the values $s_{\mathit{k}}$, the sines of the rotations $Q_{\mathit{k}}$, for $\mathit{k}=1,2,\dots ,n$.

6 Error Indicators and Warnings

7 Accuracy

8 Parallelism and Performance

9 Further Comments

10 Example