NAG FL Interface
f06hmf (zrot)

Settings help

FL Name Style:


FL Specification Language:


1 Purpose

f06hmf applies a plane rotation with a real cosine and complex sine to two complex vectors.

2 Specification

Fortran Interface
Subroutine f06hmf ( n, cx, incx, cy, incy, c, s)
Integer, Intent (In) :: n, incx, incy
Real (Kind=nag_wp), Intent (In) :: c
Complex (Kind=nag_wp), Intent (In) :: s
Complex (Kind=nag_wp), Intent (Inout) :: cx(*), cy(*)
C Header Interface
#include <nag.h>
void  f06hmf_ (const Integer *n, Complex cx[], const Integer *incx, Complex cy[], const Integer *incy, const double *c, const Complex *s)
The routine may be called by the names f06hmf, nagf_blas_zrot or its LAPACK name zrot.

3 Description

f06hmf applies a plane rotation, where the cosine is real and the sine is complex, to two n-element complex vectors x and y:
( xT yT ) ( c s -s¯ c ) ( xT yT ) .  

4 References

None.

5 Arguments

1: n Integer Input
On entry: n, the number of elements in x and y.
2: cx(*) Complex (Kind=nag_wp) array Input/Output
Note: the dimension of the array cx must be at least max(1, 1+(n-1) ×|incx| ) .
On entry: the n-element vector x.
If incx>0, xi must be stored in cx(1+(i-1)×incx), for i=1,2,,n.
If incx<0, xi must be stored in cx(1-(n-i)×incx), for i=1,2,,n.
Intermediate elements of cx are not referenced.
On exit: the transformed vector x stored in the array elements used to supply the original vector x.
Intermediate elements of cx are unchanged.
3: incx Integer Input
On entry: the increment in the subscripts of cx between successive elements of x.
4: cy(*) Complex (Kind=nag_wp) array Input/Output
Note: the dimension of the array cy must be at least max(1, 1+(n-1) ×|incy| ) .
On entry: the n-element vector y.
If incy>0, yi must be stored in cy(1+(i-1)×incy), for i=1,2,,n.
If incy<0, yi must be stored in cy(1-(n-i)×incy), for i=1,2,,n.
Intermediate elements of cy are not referenced.
On exit: the transformed vector y.
Intermediate elements of cy are unchanged.
5: incy Integer Input
On entry: the increment in the subscripts of cy between successive elements of y.
6: c Real (Kind=nag_wp) Input
On entry: the value c, the cosine of the rotation.
7: s Complex (Kind=nag_wp) Input
On entry: the value s, the sine of the rotation.

6 Error Indicators and Warnings

None.

7 Accuracy

Not applicable.

8 Parallelism and Performance

Background information to multithreading can be found in the Multithreading documentation.
f06hmf is not threaded in any implementation.

9 Further Comments

None.

10 Example

None.