NAG Library Routine Document
E04NLF/E04NLA
1 Purpose
To supply optional parameters to
E04NKF/E04NKA from an external file. More precisely, E04NLF must be used to supply optional parameters to
E04NKF and E04NLA must be used to supply optional parameters to
E04NKA.
E04NLA is a version of E04NLF 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 E04NLA.
2 Specification
2.1 Specification for E04NLF
2.2 Specification for E04NLA
3 Description
E04NLF/E04NLA may be used to supply values for optional parameters to
E04NKF/E04NKA. E04NLF/E04NLA reads an external file and each line of the file defines a single optional parameter. It is only necessary to supply values for those parameters whose values are to be different from their default values.
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 double precision 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.
The file containing the options must start with
Begin and must finish with
End. An example of a valid options file is:
Begin * Example options file
Print level = 5
End
For E04NLF each line of the file is normally printed as it is read, on the current advisory message unit (see
X04ABF), but printing may be suppressed using the keyword
Nolist. To suppress printing of
Begin,
Nolist must be the first option supplied as in the file:
Begin
Nolist
Print level = 5
End
Printing will automatically be turned on again after a call to
E04NKF or E04NLF and may be turned on again at any time using the keyword
List.
For E04NLA 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
E04NKF/E04NKA 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
E04NKF/E04NKA.
A complete list of optional parameters, their abbreviations, synonyms and default values is given in
Section 11 in E04NKF/E04NKA.
4 References
None.
5 Parameters
- 1: IOPTNS – INTEGERInput
-
On entry: the unit number of the options file to be read.
Constraint:
0≤IOPTNS≤99.
- 2: INFORM – INTEGEROutput
-
Note: for E04NLA, INFORM does not occur in this position in the parameter list. See the additional parameters described below.
On exit: contains zero if the options file has been successfully read and a
value>0 otherwise (see
Section 6).
- Note: the following are additional parameters for specific use with E04NLA. Users of E04NLF therefore need not read the remainder of this description.
- 2: LWSAV(20) – LOGICAL arrayCommunication Array
- 3: IWSAV(380) – INTEGER arrayCommunication Array
- 4: RWSAV(285) – double precision arrayCommunication Array
The arrays
LWSAV,
IWSAV and
RWSAV must not be altered between calls to any of the routines E04NLA,
E04NKA,
E04NMA or
E04WBF.
- 5: INFORM – INTEGEROutput
Note: see the parameter description for
INFORM above.
6 Error Indicators and Warnings
Errors or warnings detected by the routine:
- INFORM=1
IOPTNS is not in the range
0,99.
- INFORM=2
Begin was found, but end-of-file was found before End was found.
- INFORM=3
end-of-file was found before Begin was found.
- INFORM=4
Not used.
- INFORM=5
One or more lines of the options file is invalid. Check that all keywords are neither ambiguous nor misspelt.
7 Accuracy
Not applicable.
8 Further Comments
E04NMF/E04NMA may also be used to supply optional parameters to
E04NKF/E04NKA.
9 Example
This example solves the same problem as the example for
E04NKF/E04NKA, but in addition illustrates the use of E04NLF/E04NLA and
E04NMF/E04NMA to set optional parameters for
E04NKF/E04NKA.
In this example the options file read by E04NLF/E04NLA is appended to the data file for the program (see
Section 9.2). It would usually be more convenient in practice to keep the data file and the options file separate.
9.1 Program Text
Note: the following programs illustrate the use of E04NLF and E04NLA.
Program Text (e04nlfe.f)
Program Text (e04nlae.f)
9.2 Program Data
Program Data (e04nlfe.d)
Program Data (e04nlae.d)
9.3 Program Results
Program Results (e04nlfe.r)
Program Results (e04nlae.r)