f06ekf (dasum) (PDF version)
F06 (blas) Chapter Contents
F06 (blas) Chapter Introduction
NAG Library Manual
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NAG Library Routine Document
f06ekf (dasum)
▸
▿
Contents
1
Purpose
2
Specification
3
Description
4
References
5
Arguments
6
Error Indicators and Warnings
7
Accuracy
8
Parallelism and Performance
9
Further Comments
10
Example
1
Purpose
f06ekf (dasum)
returns the
1
-norm of the
n
-element real vector
x
.
2
Specification
Fortran Interface
Function f06ekf (
n
,
x
,
incx
)
Real (Kind=nag_wp)
::
f06ekf
Integer, Intent (In)
::
n
,
incx
Real (Kind=nag_wp), Intent (In)
::
x(*)
C Header Interface
#include nagmk26.h
double
f06ekf_ (
const Integer *
n
,
const double
x
[]
,
const Integer *
incx
)
The routine may be called by its BLAS name
dasum
.
3
Description
f06ekf (dasum)
, returns via the function name, the
1
-norm
x
1
+
x
2
+
⋯
+
x
n
of the
n
-element real vector
x
scattered with stride
incx
.
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
– Integer
Input
On entry
:
n
, the number of elements in
x
.
2:
x
*
– Real (Kind=nag_wp) array
Input
Note:
the dimension 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.
3:
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
Parallelism and Performance
f06ekf (dasum)
is not threaded in any implementation.
9
Further Comments
None.
10
Example
None.
f06ekf (dasum) (PDF version)
F06 (blas) Chapter Contents
F06 (blas) Chapter Introduction
NAG Library Manual
© The Numerical Algorithms Group Ltd, Oxford, UK. 2017