NAG FL Interface
m01naf (realvec_​search)

1 Purpose

2 Specification

3 Description

4 References

5 Arguments

1: $\mathbf{valid}$ – Logical Input

On entry: if valid is set to .TRUE. argument checking will be performed. If valid is set to .FALSE. m01naf will be called without argument checking (which includes checking that array rv is sorted in ascending order) and the routine will return with $\mathbf{ifail}=\mathbf{0}$. See Section 9 for further details.

2: $\mathbf{rv}\left(\mathbf{m2}\right)$ – Real (Kind=nag_wp) array Input

On entry: elements m1 to m2 contain real values to be searched.

Constraint: elements m1 to m2 of rv must be sorted in ascending order.

3: $\mathbf{m1}$ – Integer Input

On entry: the index of the first element of rv to be searched.

Constraint: $\mathbf{m1}\ge 1$.

4: $\mathbf{m2}$ – Integer Input

On entry: the index of the last element of rv to be searched.

Constraint: $\mathbf{m2}\ge \mathbf{m1}$.

5: $\mathbf{item}$ – Real (Kind=nag_wp) Input

On entry: the sought-after item.

6: $\mathbf{ifail}$ – 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

$\mathbf{ifail}=2$

On entry, rv must be sorted in ascending order: $\mathbf{rv}\text{ element }〈\mathit{\text{value}}〉>\text{ element }〈\mathit{\text{value}}〉$.

$\mathbf{ifail}=3$

On entry, $\mathbf{m1}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{m1}\ge 1$.

$\mathbf{ifail}=4$

On entry, $\mathbf{m1}=〈\mathit{\text{value}}〉$, $\mathbf{m2}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{m1}\le \mathbf{m2}$.

$\mathbf{ifail}=-99$

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