NAG Library Routine Document
To supply optional parameters to H02CEF
from an external file.
H02CFF may be used to supply values for optional parameters to H02CEF
. H02CFF 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
characters, consisting of one or more items. The items associated with a given option must be separated by spaces, or equal 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 contiguous characters in Fortran 77'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 = 1
Normally each line of the file is 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
must be the first option supplied as in the file:
Print Level = 1
Printing will automatically be turned on again after a call to H02CEF
and may be turned on again at any time using the keyword List
Optional parameter settings are preserved following a call to H02CEF
, and so the keyword Defaults
is provided to allow you to reset all the optional parameters to their default values prior to a subsequent call to H02CEF
A complete list of optional parameters, their abbreviations, synonyms and default values is given in Section 11
- 1: IOPTNS – INTEGERInput
On entry: the unit number of the options file to be read.
- 2: INFORM – INTEGEROutput
: contains zero if the options file has been successfully read and a value
otherwise, as indicated below.
- IOPTNS is not in the range .
- Begin was found, but end-of-file was found before End was found.
- end-of-file was found before Begin was found.
6 Error Indicators and Warnings
If a line is not recognized as a valid option, then a warning message is output on the current advisory message unit (see X04ABF
may also be used to supply optional parameters to H02CEF
. Note that if E04NKF/E04NKA
is used in the same program as H02CEF
, then in general H02CFF will also affect the options used by E04NKF/E04NKA
This example solves the same problem as the example for H02CEF
, but in addition illustrates the use of H02CFF and H02CGF
to set optional parameters for H02CEF
In this example the options file read by H02CFF 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
Program Text (h02cffe.f90)
9.2 Program Data
Program Options (h02cffe.opt)
Program Data (h02cffe.d)
9.3 Program Results
Program Results (h02cffe.r)