nag_drscl (f06fec) (PDF version)
f06 Chapter Contents
f06 Chapter Introduction
NAG C Library Manual
NAG Library Function Document
nag_drscl (f06fec)
+
−
Contents
1
Purpose
2
Specification
3
Description
4
References
5
Arguments
6
Error Indicators and Warnings
7
Accuracy
8
Further Comments
9
Example
1 Purpose
nag_drscl (f06fec) multiplies a real vector by the reciprocal of a scalar.
2 Specification
#include <nag.h>
#include <nagf06.h>
void
nag_drscl (Integer
n
, double
alpha
, double
x
[], Integer
incx
)
3 Description
nag_drscl (f06fec) performs the operation
x
←
1
α
x
where
x
is an
n
-element real vector scattered with stride
incx
and
α
is a real nonzero scalar.
4 References
None.
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
:
alpha
≠
0.0
.
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
.
x
i
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
None.
7 Accuracy
Not applicable.
8 Further Comments
None.
9 Example
None.
nag_drscl (f06fec) (PDF version)
f06 Chapter Contents
f06 Chapter Introduction
NAG C Library Manual
© The Numerical Algorithms Group Ltd, Oxford, UK. 2012