NAG FL Interface
m01dbf (intvec_​rank)

1 Purpose

2 Specification

3 Description

4 References

5 Arguments

1: $\mathbf{iv}\left(\mathbf{m2}\right)$ – Integer array Input

On entry: elements m1 to m2 of iv must contain integer values to be ranked.

2: $\mathbf{m1}$ – Integer Input

On entry: the index of the first element of iv to be ranked.

Constraint: $\mathbf{m1}>0$.

3: $\mathbf{m2}$ – Integer Input

On entry: m2 must specify the index of the last element of iv to be ranked.

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

4: $\mathbf{order}$ – Character(1) Input

On entry: if $\mathbf{order}=\text{'A'}$, the values will be ranked in ascending (i.e., nondecreasing) order.

If $\mathbf{order}=\text{'D'}$, into descending order.

Constraint: $\mathbf{order}=\text{'A'}$ or $\text{'D'}$.

5: $\mathbf{irank}\left(\mathbf{m2}\right)$ – Integer array Output

On exit: elements m1 to m2 of irank contain the ranks of the corresponding elements of iv. Note that the ranks are in the range m1 to m2: thus, if $\mathbf{iv}\left(i\right)$ is the first element in the rank order, $\mathbf{irank}\left(i\right)$ is set to m1.

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

$\mathbf{ifail}=1$

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

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

On entry, $\mathbf{m2}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{m2}\ge 1$.

$\mathbf{ifail}=2$

On entry, order has an illegal value: $\mathbf{order}=〈\mathit{\text{value}}〉$.

$\mathbf{ifail}=-99$

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