NAG Library Routine Document

e04znf (handle_opt_get)

1

Purpose

2

Specification

3

Description

4

References

5

Arguments

1:     $\mathbf{handle}$ – Type (c_ptr)Input

On entry: the handle to the problem. It needs to be initialized by e04raf and must not be changed.

2:     $\mathbf{optstr}$ – Character(*)Input

On entry: a string identifying the option whose current value is required. See the documentation of the particular solver for information on valid options.

3:     $\mathbf{ivalue}$ – IntegerOutput

On exit: if the optional parameter supplied in optstr is an integer-valued argument, ivalue will hold its current value.

4:     $\mathbf{rvalue}$ – Real (Kind=nag_wp)Output

On exit: if the optional parameter supplied in optstr is a real-valued argument, rvalue will hold its current value.

5:     $\mathbf{cvalue}$ – Character(*)Output

Note: the string returned in cvalue will never exceed $40$ characters in length.

On exit: if the optional parameter supplied in optstr is a character-valued argument, cvalue will hold its current value.

6:     $\mathbf{optype}$ – IntegerOutput

On exit: indicates whether the optional parameter supplied in optstr is an integer, real or character-valued argument and hence which of ivalue, rvalue or cvalue holds the current value.

$\mathbf{optype}=1$

optstr is an integer-valued optional parameter; its current value has been returned in ivalue.

$\mathbf{optype}=2$

optstr is a real-valued optional parameter; its current value has been returned in rvalue.

$\mathbf{optype}=3$

optstr is a character-valued optional parameter; its current value has been returned in cvalue.

7:     $\mathbf{ifail}$ – IntegerInput/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 3.4 in How to Use the NAG Library and its Documentation 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

$\mathbf{ifail}=1$

The supplied handle does not define a valid handle to the data structure for the NAG optimization modelling suite. It has not been initialized by e04raf or it has been corrupted.

$\mathbf{ifail}=11$

On entry, the option supplied in optstr was not recognized: $\mathbf{optstr}=〈\mathit{\text{value}}〉$.

$\mathbf{ifail}=41$

On entry, optstr indicates a character optional parameter, but cvalue is too short to hold the stored value. The returned value will be truncated.

$\mathbf{ifail}=-99$

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

See Section 3.9 in How to Use the NAG Library and its Documentation for further information.

$\mathbf{ifail}=-399$

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

See Section 3.8 in How to Use the NAG Library and its Documentation for further information.

$\mathbf{ifail}=-999$

Dynamic memory allocation failed.

See Section 3.7 in How to Use the NAG Library and its Documentation for further information.

7

Accuracy

8

Parallelism and Performance

9

Further Comments

10

Example