E04VLF (PDF version)
E04 Chapter Contents
E04 Chapter Introduction
NAG Library Manual

NAG Library Routine Document

E04VLF

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.

 Contents

    1  Purpose
    7  Accuracy
    10  Example

1  Purpose

E04VLF may be used to supply individual optional parameters to E04VHF. The initialization routine E04VGF must have been called before calling E04VLF.

2  Specification

SUBROUTINE E04VLF ( STRING, CW, IW, RW, IFAIL)
INTEGER  IW(*), IFAIL
REAL (KIND=nag_wp)  RW(*)
CHARACTER(*)  STRING
CHARACTER(8)  CW(*)

3  Description

E04VLF may be used to supply values for optional parameters to E04VHF. It is only necessary to call E04VLF for those arguments whose values are to be different from their default values. One call to E04VLF sets one argument 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 =. 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 40 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.
For E04VLF, each user-specified option is not normally printed as it is defined, but this printing may be turned on using the keyword List. Thus the statement
CALL E04VLF ('List', CW, IW, RW, IFAIL)
turns on printing of this and subsequent options. Printing may be turned off again using the keyword Nolist.
Optional parameter settings are preserved following a call to E04VHF 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 E04VHF.
A complete list of optional parameters, their abbreviations, synonyms and default values is given in Section 12 in E04VHF.

4  References

None.

5  Arguments

1:     STRING – CHARACTER(*)Input
On entry: a single valid option string (see Section 3 in E04VLF and Section 12 in E04VHF).
2:     CW* – CHARACTER(8) arrayCommunication Array
Note: the dimension of the array CW must be at least LENCW (see E04VGF).
3:     IW* – INTEGER arrayCommunication Array
Note: the dimension of the array IW must be at least LENIW (see E04VGF).
4:     RW* – REAL (KIND=nag_wp) arrayCommunication Array
Note: the dimension of the array RW must be at least LENRW (see E04VGF).
5:     IFAIL – INTEGERInput/Output
On entry: IFAIL must be set to 0, -1​ or ​1. If you are unfamiliar with this argument you should refer to Section 3.4 in How to Use the NAG Library and its Documentation for details.
For environments where it might be inappropriate to halt program execution when an error is detected, the value -1​ 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 argument, the recommended value is 0. 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 or -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
The initialization routine E04VGF has not been called.
IFAIL=2
The supplied option is invalid. Check that the keywords are neither ambiguous nor misspelt.
IFAIL=-99
An unexpected error has been triggered by this routine. Please contact NAG.
See Section 3.9 in How to Use the NAG Library and its Documentation for further information.
IFAIL=-399
Your licence key may have expired or may not have been installed correctly.
See Section 3.8 in How to Use the NAG Library and its Documentation for further information.
IFAIL=-999
Dynamic memory allocation failed.
See Section 3.7 in How to Use the NAG Library and its Documentation for further information.

7  Accuracy

Not applicable.

8  Parallelism and Performance

E04VLF is not threaded in any implementation.

9  Further Comments

E04VKF, E04VMF or E04VNF may also be used to supply optional parameters to E04VHF.

10  Example

See Section 10 in E04VKF.

E04VLF (PDF version)
E04 Chapter Contents
E04 Chapter Introduction
NAG Library Manual

© The Numerical Algorithms Group Ltd, Oxford, UK. 2016