E05 Chapter Contents
E05 Chapter Introduction
NAG Library Manual

# NAG Library Routine DocumentE05JLF

Note:  before using this routine, please read the Users' Note for your implementation to check the interpretation of bold italicised terms and other implementation-dependent details.

## 1  Purpose

E05JLF is used to get the value of a real E05JBF optional parameter. E05JLF can be used before or after calling E05JBF, but the initialization routine E05JAF must have been called before calling E05JLF.

## 2  Specification

 SUBROUTINE E05JLF ( OPTSTR, RVALUE, COMM, LCOMM, IFAIL)
 INTEGER LCOMM, IFAIL REAL (KIND=nag_wp) RVALUE, COMM(LCOMM) CHARACTER(*) OPTSTR

## 3  Description

E05JLF obtains the current value of a real-valued optional parameter. For example
```CALL E05JLF ('Local Searches Tolerance', LOCTOL, COMM, LCOMM, IFAIL)
```
will result in the value of the optional parameter Local Searches Tolerance being output in LOCTOL.
A complete list of optional parameters, their symbolic names and default values is given in Section 11 in E05JBF.

None.

## 5  Parameters

1:     OPTSTR – CHARACTER(*)Input
On entry: a string identifying a real-valued optional parameter (as described in Section 11 in E05JBF).
2:     RVALUE – REAL (KIND=nag_wp)Output
On exit: if ${\mathbf{IFAIL}}={\mathbf{0}}$ on exit, RVALUE contains the real value associated with the optional parameter in OPTSTR.
3:     COMM(LCOMM) – REAL (KIND=nag_wp) arrayCommunication Array
On entry: communication data as initialized by E05JAF.
4:     LCOMM – INTEGERInput
On entry: the dimension of the array COMM as declared in the (sub)program from which E05JLF is called.
Constraint: ${\mathbf{LCOMM}}\ge 100$.
5:     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

If on entry ${\mathbf{IFAIL}}={\mathbf{0}}$ or $-{\mathbf{1}}$, explanatory error messages are output on the current error message unit (as defined by X04AAF).
Errors or warnings detected by the routine:
${\mathbf{IFAIL}}=1$
 On entry, ${\mathbf{LCOMM}}<100$, or the initialization routine E05JAF has not been called.
${\mathbf{IFAIL}}=2$
The optional parameter given in OPTSTR is invalid. A keyword or keyword combination was not recognized.

Not applicable.

None.

## 9  Example

See Section 9 in E05JCF.