NAG Library Routine Document

f06gdf  (zscal)

 Contents

    1  Purpose
    7  Accuracy
    10  Example

1
Purpose

f06gdf (zscal) scales a complex vector by a complex scalar.

2
Specification

Fortran Interface
Subroutine f06gdf ( n, alpha, x, incx)
Integer, Intent (In):: n, incx
Complex (Kind=nag_wp), Intent (In):: alpha
Complex (Kind=nag_wp), Intent (Inout):: x(*)
C Header Interface
#include nagmk26.h
void  f06gdf_ ( const Integer *n, const Complex *alpha, Complex x[], const Integer *incx)
The routine may be called by its BLAS name zscal.

3
Description

f06gdf (zscal) performs the operation
xαx  
where x is an n-element complex vector scattered with stride incx, and α is a complex scalar.

4
References

Lawson C L, Hanson R J, Kincaid D R and Krogh F T (1979) Basic linear algebra supbrograms for Fortran usage ACM Trans. Math. Software 5 308–325

5
Arguments

1:     n – IntegerInput
On entry: n, the number of elements in x.
2:     alpha – Complex (Kind=nag_wp)Input
On entry: the scalar α.
3:     x* – Complex (Kind=nag_wp) arrayInput/Output
Note: the dimension of the array x must be at least max1, 1+n-1 ×incx .
On entry: the n-element vector x. xi must be stored in x1+i-1×incx, for i=1,2,,n.
Intermediate elements of x are not referenced.
On exit: the vector αx stored in the array elements used to supply the original vector xy.
Intermediate elements of x are unchanged.
4:     incx – IntegerInput
On entry: the increment in the subscripts of x between successive elements of x.
Constraint: incx>0.

6
Error Indicators and Warnings

None.

7
Accuracy

Not applicable.

8
Parallelism and Performance

f06gdf (zscal) is not threaded in any implementation.

9
Further Comments

None.

10
Example

None.
© The Numerical Algorithms Group Ltd, Oxford, UK. 2017