NAG FL Interface
x03abf (complex_​prec)

1 Purpose

2 Specification

3 Description

4 References

5 Arguments

1: $\mathbf{a}\left(\mathbf{isizea}\right)$ – Complex (Kind=nag_wp) array Input

On entry: the elements of the first vector.

The $i$th vector element is stored in the array element $\mathbf{a}\left(\left(i-1\right)\times \mathbf{istepa}+1\right)$. In your subroutine from which x03abf is called, a can be part of a multidimensional array and the actual argument must be the array element containing the first vector element.

2: $\mathbf{isizea}$ – Integer Input

On entry: the dimension of the array a as declared in the (sub)program from which x03abf is called.

The upper bound for isizea is found by multiplying together the dimensions of a as declared in your subroutine from which x03abf is called, subtracting the starting position and adding $1$.

Constraint: $\mathbf{isizea}\ge \left(\mathbf{n}-1\right)\times \mathbf{istepa}+1$.

3: $\mathbf{b}\left(\mathbf{isizeb}\right)$ – Complex (Kind=nag_wp) array Input

On entry: the elements of the second vector.

The $i$th vector element is stored in the array element $\mathbf{b}\left(\left(i-1\right)\times \mathbf{istepb}+1\right)$. In your subroutine from which x03abf is called, b can be part of a multidimensional array and the actual argument must be the array element containing the first vector element.

4: $\mathbf{isizeb}$ – Integer Input

On entry: the dimension of the array b as declared in the (sub)program from which x03abf is called.

The upper bound for isizeb is found by multiplying together the dimensions of b as declared in your subroutine from which x03abf is called, subtracting the starting position and adding $1$.

Constraint: $\mathbf{isizeb}\ge \left(\mathbf{n}-1\right)\times \mathbf{istepb}+1$.

5: $\mathbf{n}$ – Integer Input

On entry: $n$, the number of elements in the scalar product.

6: $\mathbf{istepa}$ – Integer Input

On entry: the step length between elements of the first vector in array a.

Constraint: $\mathbf{istepa}>0$.

7: $\mathbf{istepb}$ – Integer Input

On entry: the step length between elements of the second vector in array b.

Constraint: $\mathbf{istepb}>0$.

8: $\mathbf{cx}$ – Complex (Kind=nag_wp) Input

On entry: the initial value $c$.

9: $\mathbf{dx}$ – Complex (Kind=nag_wp) Output

On exit: the result $d$.

10: $\mathbf{sw}$ – Logical Input

On entry: the precision to be used in the calculation.

$\mathbf{sw}=\mathrm{.TRUE.}$

additional precision.

$\mathbf{sw}=\mathrm{.FALSE.}$

basic precision.

11: $\mathbf{ifail}$ – Integer Input/Output

On entry: ifail must be set to $0$, $-1\text{ or }1$. If you are unfamiliar with this argument you should refer to Section 4 in the Introduction to the NAG Library FL Interface for details.

For environments where it might be inappropriate to halt program execution when an error is detected, the value $-1\text{ or }1$ is recommended. If the output of error messages is undesirable, then the value $1$ is recommended. Otherwise, if you are not familiar with this argument, the recommended value is $0$. When the value $-\mathbf{1}\text{ or }\mathbf{1}$ is used it is essential to test the value of ifail on exit.

On exit: $\mathbf{ifail}=\mathbf{0}$ unless the routine detects an error or a warning has been flagged (see Section 6).

6 Error Indicators and Warnings

$\mathbf{ifail}=1$

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

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

$\mathbf{ifail}=2$

On entry, $\mathbf{isizea}=〈\mathit{\text{value}}〉$, $\mathbf{n}=〈\mathit{\text{value}}〉$ and $\mathbf{istepa}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{isizea}\ge \left(\mathbf{n}-1\right)\times \mathbf{istepa}+1$.

On entry, $\mathbf{isizeb}=〈\mathit{\text{value}}〉$, $\mathbf{n}=〈\mathit{\text{value}}〉$ and $\mathbf{istepb}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{isizeb}\ge \left(\mathbf{n}-1\right)\times \mathbf{istepb}+1$.

$\mathbf{ifail}=-99$

An unexpected error has been triggered by this routine. Please contact NAG.

See Section 7 in the Introduction to the NAG Library FL Interface for further information.

$\mathbf{ifail}=-399$

Your licence key may have expired or may not have been installed correctly.

See Section 8 in the Introduction to the NAG Library FL Interface for further information.

$\mathbf{ifail}=-999$

Dynamic memory allocation failed.

See Section 9 in the Introduction to the NAG Library FL Interface for further information.

7 Accuracy

8 Parallelism and Performance

9 Further Comments

10 Example

10.1 Program Text

10.2 Program Data

10.3 Program Results