NAG Library Routine Document

G02ZLF

1  Purpose

2  Specification

3  Description

4  References

5  Parameters

1:     OPTSTR – CHARACTER(*)Input

On entry: a string identifying the option whose current value is required. See Section 11 in G02QGF for information on valid options. In addition, the following is a valid option:

$\mathbf{Identify}$

G02ZLF returns in CVALUE the routine name supplied to G02ZKF when the optional parameter arrays IOPTS and OPTS were initialized.

2:     IVALUE – INTEGEROutput

On exit: if the optional parameter supplied in OPTSTR is an integer valued parameter, IVALUE will hold its current value.

3:     RVALUE – REAL (KIND=nag_wp)Output

On exit: if the optional parameter supplied in OPTSTR is a real valued parameter, RVALUE will hold its current value.

4:     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 parameter, CVALUE will hold its current value, unless Identify is specified, see OPTSTR.

5:     OPTYPE – INTEGEROutput

On exit: indicates whether the optional parameter supplied in OPTSTR is an integer, real or character valued parameter 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.

6:     IOPTS($*$) – INTEGER arrayCommunication Array

Note: the contents of IOPTS must not have been altered between calls to G02ZKF, G02ZLF and the selected problem solving routine.

On entry: the contents of IOPTS must not have been altered between calls to G02ZKF, G02ZLF and the selected problem solving routine.

7:     OPTS($*$) – REAL (KIND=nag_wp) arrayCommunication Array

Note: the contents of OPTS must not have been altered between calls to G02ZKF, G02ZLF and the selected problem solving routine.

On entry: the contents of OPTS must not have been altered between calls to G02ZKF, G02ZLF and the selected problem solving routine.

8:     IFAIL – INTEGERInput/Output

On entry: IFAIL must be set to $0$, $-1\text{ or }1$. If you are unfamiliar with this parameter you should refer to Section 3.3 in the Essential Introduction 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 parameter, 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

$\mathbf{IFAIL}=11$

On entry, the option in OPTSTR was not recognized.

$\mathbf{IFAIL}=41$

On entry, OPTSTR identifies a character valued optional parameter. However, CVALUE is too short to contain the entire character string. The value returned in CVALUE will be therefore be truncated.

$\mathbf{IFAIL}=61$

On entry, either the optional parameter arrays have not been initialized or they have been corrupted.

7  Accuracy

8  Further Comments

9  Example