NAG Library Function Document

nag_dwaxpby (f16ehc)

1  Purpose

2  Specification

3  Description

4  References

5  Arguments

1:     n – IntegerInput

On entry: $n$, the number of elements in $x$, $y$ and $w$.

Constraint: $\mathbf{n}\ge 0$.

2:     alpha – doubleInput

On entry: the scalar $\alpha$.

3:     x[$\mathit{dim}$] – const doubleInput

Note: the dimension, dim, of the array x must be at least $\max \left(1,1+\left(\mathbf{n}-1\right)\times \left|\mathbf{incx}\right|\right)$.

On entry: the vector $x$. Element $x_{\mathit{i}}$ is stored in $\mathbf{x}\left[\left(\mathit{i}-1\right)\times \left|\mathbf{incx}\right|\right]$, for $\mathit{i}=1,2,\dots ,n$.

4:     incx – IntegerInput

On entry: the increment in the subscripts of x between successive elements of $x$.

Constraint: $\mathbf{incx}\ne 0$.

5:     beta – doubleInput

On entry: the scalar $\beta$.

6:     y[$\mathit{dim}$] – const doubleInput

Note: the dimension, dim, of the array y must be at least $\max \left(1,1+\left(\mathbf{n}-1\right)\times \left|\mathbf{incy}\right|\right)$.

On entry: the vector $y$. Element $y_{\mathit{i}}$ is stored in $\mathbf{y}\left[\left(\mathit{i}-1\right)\times \left|\mathbf{incy}\right|\right]$, for $\mathit{i}=1,2,\dots ,n$.

7:     incy – IntegerInput

On entry: the increment in the subscripts of y between successive elements of $y$.

Constraint: $\mathbf{incy}\ne 0$.

8:     w[$\mathit{dim}$] – doubleOutput

Note: the dimension, dim, of the array w must be at least $\max \left(1,1+\left(\mathbf{n}-1\right)\times \left|\mathbf{incw}\right|\right)$.

On exit: $w$, the result of the scaled-vector addition. Element $w_{\mathit{i}}$ is stored in $\mathbf{w}\left[\left(\mathit{i}-1\right)\times \left|\mathbf{incw}\right|\right]$, for $\mathit{i}=1,2,\dots ,n$.

9:     incw – IntegerInput

On entry: the increment in the subscripts of w between successive elements of $w$.

Constraint: $\mathbf{incw}\ne 0$.

10:   fail – NagError *Input/Output

The NAG error argument (see Section 3.6 in the Essential Introduction).

6  Error Indicators and Warnings

NE_BAD_PARAM

On entry, argument $〈\mathit{\text{value}}〉$ had an illegal value.

NE_INT

On entry, $\mathbf{incw}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{incw}\ne 0$.

On entry, $\mathbf{incx}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{incx}\ne 0$.

On entry, $\mathbf{incy}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{incy}\ne 0$.

On entry, $\mathbf{n}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{n}\ge 0$.

7  Accuracy

8  Further Comments

9  Example

9.1  Program Text

Program Text (f16ehce.c)

9.2  Program Data

Program Data (f16ehce.d)

9.3  Program Results

Program Results (f16ehce.r)