E04 Chapter Contents
E04 Chapter Introduction
NAG Library Manual

# NAG Library Routine DocumentE04DKF/E04DKA

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

To supply individual optional parameters to E04DGF/E04DGA. More precisely, E04DKF must be used to supply optional parameters to E04DGF and E04DKA must be used to supply optional parameters to E04DGA.
E04DKA is a version of E04DKF that has additional parameters in order to make it safe for use in multithreaded applications (see Section 5). The initialization routine E04WBF must have been called before calling E04DKA.

## 2  Specification

### 2.1  Specification for E04DKF

 SUBROUTINE E04DKF ( STR)
 CHARACTER(*) STR

### 2.2  Specification for E04DKA

 SUBROUTINE E04DKA ( STR, LWSAV, IWSAV, RWSAV, INFORM)
 INTEGER IWSAV(610), INFORM REAL (KIND=nag_wp) RWSAV(475) LOGICAL LWSAV(120) CHARACTER(*) STR

## 3  Description

E04DKF/E04DKA may be used to supply values for optional parameters to E04DGF/E04DGA. It is only necessary to call E04DKF/E04DKA for those parameters whose values are to be different from their default values. One call to E04DKF/E04DKA sets one parameter value.
Each optional parameter is defined by a single character string, of up to $72$ characters, consisting of one or more items. The items associated with a given option must be separated by spaces, or equals signs $\left[=\right]$. Alphabetic characters may be upper or lower case. The string
`Print Level = 1`
is an example of a string used to set an optional parameter. For each option the string contains one or more of the following items:
 – a mandatory keyword; – a phrase that qualifies the keyword; – a number that specifies an integer or real value. Such numbers may be up to $16$ contiguous characters in Fortran's I, F, E or D formats, terminated by a space if this is not the last item on the line.
Blank strings and comments are ignored. A comment begins with an asterisk (*) and all subsequent characters in the string are regarded as part of the comment.
For E04DKF, each user-specified option is normally printed as it is defined, on the current advisory message unit (see X04ABF), but this printing may be suppressed using the keyword Nolist. Thus the statement
``` CALL E04DKF ('Nolist')
```
suppresses printing of this and subsequent options. Printing will automatically be turned on again after a call to E04DGF and may be turned on again at any time using the keyword List.
For E04DKA printing is turned off by default, but may be turned on at any time using the keyword List.
Optional parameter settings are preserved following a call to E04DGF/E04DGA and so the keyword Defaults is provided to allow you to reset all the optional parameters to their default values before a subsequent call to E04DGF/E04DGA.
A complete list of optional parameters, their abbreviations, synonyms and default values is given in Section 11 in E04DGF/E04DGA.

None.

## 5  Parameters

1:     STR – CHARACTER(*)Input
On entry: a single valid option string (as described in Section 3 and in Section 11 in E04DGF/E04DGA).
Note: the following are additional parameters for specific use with E04DKA. Users of E04DKF therefore need not read the remainder of this description.
2:     LWSAV($120$) – LOGICAL arrayCommunication Array
3:     IWSAV($610$) – INTEGER arrayCommunication Array
4:     RWSAV($475$) – REAL (KIND=nag_wp) arrayCommunication Array
The arrays LWSAV, IWSAV and RWSAV must not be altered between calls to any of the routines E04DKA, E04DGA, E04DJA or E04WBF.
5:     INFORM – INTEGEROutput
On exit: contains zero if a valid option string has been supplied and a $\text{value}>0$ otherwise (see Section 6).

## 6  Error Indicators and Warnings

Errors or warnings detected by the routine:
${\mathbf{INFORM}}=5$
The supplied option is invalid. Check that the keywords are neither ambiguous nor misspelt.

Not applicable.