e05zkf either initializes or resets the optional parameter arrays or sets a single optional parameter for supported problem solving routines in Chapter E05. The following routines are supported:

2 Specification

Fortran Interface

Subroutine e05zkf (

optstr, iopts, liopts, opts, lopts, ifail)

Integer, Intent (In)	::	liopts, lopts
Integer, Intent (Inout)	::	iopts(liopts), ifail
Real (Kind=nag_wp), Intent (Inout)	::	opts(lopts)
Character (*), Intent (In)	::	optstr

C Header Interface

#include <nag.h>

void	e05zkf_ (const char optstr, Integer iopts[], const Integer liopts, double opts[], const Integer lopts, Integer ifail, const Charlen length_optstr)

The routine may be called by the names e05zkf or nagf_glopt_optset.

3 Description

e05zkf has three purposes: to initialize optional parameter arrays; to reset all optional parameters to their default values; or to set a single optional parameter to a user-supplied value.

Optional parameters and their values are, in general, presented as a character string, optstr, of the form ‘

option = optval

’; alphabetic characters can be supplied in either upper or lower case. Both

option

and

optval

may consist of one or more tokens separated by white space. The tokens that comprise

optval

will normally be either an integer, real or character value as defined in the description of the specific optional argument. In addition all optional parameters can take an

optval

DEFAULT which resets the optional parameter to its default value.

It is imperative that optional parameter arrays are initialized before any options are set, before the relevant problem solving routine is called and before any options are queried using e05zlf. To initialize the optional parameter arrays iopts and opts for a specific problem solving routine, the option Initialize is used with

optval

identifying the problem solving routine to be called. For example, to initialize optional parameter arrays to be passed to e05saf, e05zkf is called as follows:

Call e05zkf('Initialize = e05saf', iopts, liopts, opts, lopts, ifail)

Note that the routine name may be abbreviated to just the first five letters of the ‘short’ name, or by omitting the nagf_ or glopt_ prefixes of the ‘long’ name. So the above may be equivalently specified as 'Initialize = e05sa' or 'Initialize = bnd_pso'.

Information relating to available option names and their corresponding valid values is given in Section 12 in e05saf, e05sbf, e05ucf and e05usf.

4 References

None.

5 Arguments

1: $optstr$ – Character(*) Input

On entry: a string identifying the option to be set.

$Initialize = routine name$: Initialize the optional parameter arrays iopts and opts for use with routine $routine name$ , where $routine name$ is the name associated with the routine of interest.
$Defaults$: Resets all options to their default values.

$option = optval$: See Section 12 in e05saf, e05sbf, e05ucf and e05usf for details of valid values for $option$ and $optval$ . The equals sign ( $=$ ) delimiter must be used to separate the $option$ from its $optval$ value.

optstr is case insensitive. Each token in the

option

and

optval

component must be separated by at least one space.

2: $iopts (liopts)$ – Integer array Communication Array

On entry: optional parameter array.

If optstr has the form

Initialize = routine name

, the contents of iopts need not be set.

Otherwise, iopts must not have been altered since the last call to e05zkf, e05zlf or the selected problem solving routine.

On exit: dependent on the contents of optstr, either an initialized, reset or updated version of the optional parameter array.

3: $liopts$ – Integer Input

On entry: the length of the array iopts.

Constraint: unless otherwise stated in the documentation for a specific, supported, problem solving routine,

liopts \geq 100

4: $opts (lopts)$ – Real (Kind=nag_wp) array Communication Array

On entry: optional parameter array.

If optstr has the form

Initialize = routine name

, the contents of opts need not be set.

Otherwise, opts must not have been altered since the last call to e05zkf, e05zlf or the selected problem solving routine.

On exit: dependent on the contents of optstr, either an initialized, reset or updated version of the optional parameter array.

5: $lopts$ – Integer Input

On entry: the length of the array opts.

Constraint: unless otherwise stated in the documentation for a specific, supported, problem solving routine,

lopts \geq 100

6: $ifail$ – Integer Input/Output

On entry: ifail must be set to

0

−1

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

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:

$ifail = 11$: On entry, the optional parameter in optstr was not recognized: $optstr = ⟨ value ⟩$ .

$ifail = 12$: On entry, the expected delimiter ‘ $=$ ’ was not found in optstr: $optstr = ⟨ value ⟩$ .

$ifail = 13$: On entry, could not convert the specified $optval$ to an integer: $optstr = ⟨ value ⟩$ .

On entry, could not convert the specified $optval$ to a real: $optstr = ⟨ value ⟩$ .

The $option$ in optstr is associated with a numerical value. However, the $optval$ , $⟨ value ⟩$ , present in optstr could not be fully interpreted.

$ifail = 14$: On entry, the $option$ in optstr has been detected as Initialize, however the $optval$ , $⟨ value ⟩$ , associated with optstr has not been recognized as a valid routine name.

$ifail = 15$: On entry, the $optval$ supplied for the integer optional parameter is not valid.
$optstr = ⟨ value ⟩$ .

$ifail = 16$: On entry, the $optval$ supplied for the real optional parameter is not valid.
$optstr = ⟨ value ⟩$ .

$ifail = 17$: On entry, the optional parameter in optstr was not recognized: $optstr = ⟨ value ⟩$ .

On entry, the $optval$ supplied for the character optional parameter is not valid.
$optstr = ⟨ value ⟩$ .

$ifail = 21$: On entry, either the option arrays have not been initialized or they have been corrupted.

On entry, the optional parameter in optstr was not recognized: $optstr = ⟨ value ⟩$ .

$ifail = 31$: On entry, $liopts = ⟨ value ⟩$ .
Constraint: $liopts \geq ⟨ value ⟩$ .

$ifail = 51$: On entry, $lopts = ⟨ value ⟩$ .
Constraint: $lopts \geq ⟨ value ⟩$ .

$ifail = - 99$: 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

e05zkf 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.

9 Further Comments

Some options have default values which are problem dependent. For example the option Maximum Iterations Completed for e05saf has the default value

1000 \times ndim

. If options such as this are set, they may only be set to constant values. If such an option is reset to its DEFAULT value its dependence on the specific problem will be restored.

10 Example

See the example programs associated with the problem solving routine you wish to use for a demonstration of how to use e05zkf to initialize option arrays and set options.

NAG Library Manual, Mark 27.3

Interfaces: FL CL CPP AD

NAG FL Interface Introduction

E05 (Glopt) Chapter Contents

E05 (Glopt) Chapter Introduction

e05zk: FL CL CPP AD

NAG FL Interfacee05zkf (optset)

▸▿ Contents

1 Purpose