f06ea computes the scalar product of two real vectors.

Syntax

C#
public static double f06ea(
	int n,
	double[] x,
	int incx,
	double[] y,
	int incy,
	out int ifail
)
Visual Basic
Public Shared Function f06ea ( _
	n As Integer, _
	x As Double(), _
	incx As Integer, _
	y As Double(), _
	incy As Integer, _
	<OutAttribute> ByRef ifail As Integer _
) As Double
Visual C++
public:
static double f06ea(
	int n, 
	array<double>^ x, 
	int incx, 
	array<double>^ y, 
	int incy, 
	[OutAttribute] int% ifail
)
F#
static member f06ea : 
        n : int * 
        x : float[] * 
        incx : int * 
        y : float[] * 
        incy : int * 
        ifail : int byref -> float 

Parameters

n
Type: System..::..Int32
On entry: n, the number of elements in x and y.
x
Type: array<System..::..Double>[]()[][]
An array of size [dim1]
Note: the dimension of the array x must be at least max1,1+n-1×incx.
On entry: the n-element vector x.
If incx>0, xi must be stored in x[1+i-1×incx], for i=1,2,,n.
If incx<0, xi must be stored in x[1-n-i×incx], for i=1,2,,n.
Intermediate elements of x are not referenced.
incx
Type: System..::..Int32
On entry: the increment in the subscripts of x between successive elements of x.
y
Type: array<System..::..Double>[]()[][]
An array of size [dim1]
Note: the dimension of the array y must be at least max1,1+n-1×incy.
On entry: the n-element vector y.
If incy>0, yi must be stored in y[1+i-1×incy], for i=1,2,,n.
If incy<0, yi must be stored in y[1-n-i×incy], for i=1,2,,n.
Intermediate elements of y are not referenced.
incy
Type: System..::..Int32
On entry: the increment in the subscripts of y between successive elements of y.
ifail
Type: System..::..Int32%
On exit: ifail=0 unless the method detects an error (see [Error Indicators and Warnings]).

Return Value

f06ea computes the scalar product of two real vectors.

Description

f06ea returns the value of the scalar product
xTy
where x and y are n-element real vectors scattered with stride incx and incy respectively.

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

Error Indicators and Warnings

ifail=-9000
An error occured, see message report.
ifail=-8000
Negative dimension for array value
ifail=-6000
Invalid Parameters value
ifail=-6000
Invalid Parameters value

Accuracy

Not applicable.

Parallelism and Performance

None.

Further Comments

None.

Example

See Also