f06 Chapter Contents
f06 Chapter Introduction
NAG Library Manual

# NAG Library Function Documentnag_zrscl (f06kec)

## 1  Purpose

nag_zrscl (f06kec) multiplies a complex vector by the reciprocal of a real scalar.

## 2  Specification

 #include #include
 void nag_zrscl (Integer n, double alpha, Complex x[], Integer incx)

## 3  Description

nag_zrscl (f06kec) performs the operation
 $x←1 α x$
where $x$ is an $n$-element complex vector and $\alpha$ is a real nonzero scalar scattered with stride incx.

None.

## 5  Arguments

1:    $\mathbf{n}$IntegerInput
On entry: $n$, the number of elements in $x$.
2:    $\mathbf{alpha}$doubleInput
On entry: the scalar $\alpha$.
Constraint: ${\mathbf{alpha}}\ne 0.0$.
3:    $\mathbf{x}\left[\mathit{dim}\right]$ComplexInput/Output
Note: the dimension, dim, of the array x must be at least $\mathrm{max}\phantom{\rule{0.125em}{0ex}}\left(1,1+\left({\mathbf{n}}-1\right)×{\mathbf{incx}}\right)$.
On entry: the $n$-element vector $x$. ${x}_{\mathit{i}}$ must be stored in ${\mathbf{x}}\left[1+\left(\mathit{i}-1\right)×{\mathbf{incx}}\right]$, for $\mathit{i}=1,2,\dots ,{\mathbf{n}}$.
Intermediate elements of x are not referenced.
On exit: the updated vector $x$, stored in the same array elements used to supply the original vector.
4:    $\mathbf{incx}$IntegerInput
On entry: the increment in the subscripts of x between successive elements of $x$.
Constraint: ${\mathbf{incx}}>0$.

None.

Not applicable.

## 8  Parallelism and Performance

nag_zrscl (f06kec) makes calls to BLAS and/or LAPACK routines, which may be threaded within the vendor library used by this implementation. Consult the documentation for the vendor library for further information.
Please consult the x06 Chapter Introduction for information on how to control and interrogate the OpenMP environment used within this function. Please also consult the Users' Note for your implementation for any additional implementation-specific information.