e05jgf may be used to supply individual real optional parameters to e05jbf. The initialization routine e05jaf must have been called before calling e05jgf.

2 Specification

Fortran Interface

Subroutine e05jgf (

optstr, rvalue, comm, lcomm, ifail)

Integer, Intent (In)	::	lcomm
Integer, Intent (Inout)	::	ifail
Real (Kind=nag_wp), Intent (In)	::	rvalue
Real (Kind=nag_wp), Intent (Inout)	::	comm(lcomm)
Character (*), Intent (In)	::	optstr

C Header Interface

#include <nag.h>

void	e05jgf_ (const char optstr, const double rvalue, double comm[], const Integer lcomm, Integer ifail, const Charlen length_optstr)

The routine may be called by the names e05jgf or nagf_glopt_bnd_mcs_optset_real.

3 Description

e05jgf may be used to supply values for real optional parameters to e05jbf. It is only necessary to call e05jgf for those arguments whose values are to be different from their default values. One call to e05jgf sets one argument value.

Each real optional parameter is defined by a single character string in optstr and the corresponding value in rvalue. For example the following illustrates how the local searches tolerance could be defined:

loctol = 1.0E-10
Call e05jgf ('Local Searches Tolerance', Loctol, comm, lcomm, ifail)

A complete list of optional parameters, their symbolic names and default values is given in Section 12 in e05jbf.

4 References

None.

5 Arguments

1: $optstr$ – Character(*) Input: On entry: a string identifying a real-valued optional parameter (as described in Section 12 in e05jbf).
2: $rvalue$ – Real (Kind=nag_wp) Input: On entry: the value associated with the optional parameter in optstr.
3: $comm (lcomm)$ – Real (Kind=nag_wp) array Communication Array: On exit: comm must not be altered between calls to any of the routines e05jbf, e05jcf, e05jdf, e05jef, e05jff, e05jgf, e05jhf, e05jjf, e05jkf and e05jlf.
4: $lcomm$ – Integer Input: On entry: the dimension of the array comm as declared in the (sub)program from which e05jgf is called.

Constraint: $lcomm \geq 100$ .
5: $ifail$ – Integer Input/Output: On entry: ifail must be set to $0$ , $- 1$ or $1$ to set behaviour on detection of an error; these values have no effect when no error is detected.
A value of $0$ causes the printing of an error message and program execution will be halted; otherwise program execution continues. A value of $- 1$ means that an error message is printed while a value of $1$ means that it is not.

If halting is not appropriate, the value $- 1$ or $1$ is recommended. If message printing is undesirable, then the value $1$ is recommended. Otherwise, the value $0$ is recommended. When the value $- 1$ or $1$ is used it is essential to test the value of ifail on exit.

On exit: $ifail = 0$ unless the routine detects an error or a warning has been flagged (see Section 6).

6 Error Indicators and Warnings

If on entry

ifail = 0

- 1

, explanatory error messages are output on the current error message unit (as defined by x04aaf).

Errors or warnings detected by the routine:

$ifail = 1$: Initialization routine e05jaf has not been called.

On entry, $lcomm = ⟨ value ⟩$ .
Constraint: $lcomm \geq 100$ .

$ifail = 2$: The supplied optional parameter is invalid. A keyword or keyword combination was not recognized.

$ifail = 3$: Attempt to assign an out-of-bounds value of Infinite Bound Size ( $infbnd$ ): $infbnd = ⟨ value ⟩$ .

Attempt to assign too small a value of Local Searches Tolerance ( $loctol$ ): $loctol = ⟨ value ⟩$ .

Attempt to assign too small a value of Target Objective Error ( $objerr$ ): $objerr = ⟨ value ⟩$ .

Attempt to assign too small a value of Target Objective Safeguard ( $objsfg$ ): $objsfg = ⟨ value ⟩$ .

$ifail = - 99$: 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.

$ifail = - 399$: 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.

$ifail = - 999$: Dynamic memory allocation failed.
See Section 9 in the Introduction to the NAG Library FL Interface for further information.

7 Accuracy

Not applicable.

8 Parallelism and Performance

e05jgf is threaded by NAG for parallel execution in multithreaded implementations of the NAG Library.

Please consult the X06 Chapter Introduction for information on how to control and interrogate the OpenMP environment used within this routine. Please also consult the Users' Note for your implementation for any additional implementation-specific information.