NAG CL Interface
f06fec (drscl)

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1 Purpose

f06fec multiplies a real vector by the reciprocal of a scalar.

2 Specification

#include <nag.h>
void  f06fec (Integer n, double alpha, double x[], Integer incx)
The function may be called by the names: f06fec, nag_blas_drscl or nag_drscl.

3 Description

f06fec performs the operation
x1 α x  
where x is an n-element real vector scattered with stride incx and α is a real nonzero scalar.

4 References


5 Arguments

1: n Integer Input
On entry: n, the number of elements in x.
2: alpha double Input
On entry: the scalar α.
Constraint: alpha0.0.
3: x[dim] double Input/Output
Note: the dimension, dim, of the array x must be at least max(1, 1+(n-1) ×incx ) .
On entry: the n-element vector x. xi must be stored in x[1+(i-1)×incx], for i=1,2,,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: incx Integer Input
On entry: the increment in the subscripts of x between successive elements of x.
Constraint: incx>0.

6 Error Indicators and Warnings


7 Accuracy

Not applicable.

8 Parallelism and Performance

f06fec 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.

9 Further Comments


10 Example