H Chapter Contents
H Chapter Introduction
NAG Library Manual

# NAG Library Routine DocumentH02CCF

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 optional parameters to H02CBF from an external file.

## 2  Specification

 SUBROUTINE H02CCF ( IOPTNS, INFORM)
 INTEGER IOPTNS, INFORM

## 3  Description

H02CCF may be used to supply values for optional parameters to H02CBF. H02CCF 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 equal 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 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 = 10
End
```
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, Nolist must be the first option supplied as in the file:
```Begin
Nolist
Print level = 10
End
```
Printing will automatically be turned on again after a call to H02CBF and may be turned on again at any time by you by using the keyword List.
Optional parameter settings are preserved following a call to H02CBF, 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 H02CBF.
A complete list of optional parameters, their abbreviations, synonyms and default values is given in Section 11 in H02CBF.

None.

## 5  Parameters

1:     IOPTNS – INTEGERInput
On entry: the unit number of the options file to be read.
Constraint: $0\le {\mathbf{IOPTNS}}\le 99$.
2:     INFORM – INTEGEROutput
On exit: contains zero if the options file has been successfully read and a value $\text{}>0$ otherwise, as indicated below.
${\mathbf{INFORM}}=1$
IOPTNS is not in the range $\left[0,99\right]$.
${\mathbf{INFORM}}=2$
Begin was found, but end-of-file was found before End was found.
${\mathbf{INFORM}}=3$
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).

## 7  Accuracy

Not applicable.

H02CDF may also be used to supply optional parameters to H02CBF. Note that if E04NFF/E04NFA is used in the same program as H02CBF, then in general H02CCF will also affect the options used by E04NFF/E04NFA.

## 9  Example

This example solves the same problem as the example for H02CBF, but in addition illustrates the use of H02CCF and H02CDF to set optional parameters for H02CBF.
In this example the options file read by H02CCF 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 (h02ccfe.f90)

### 9.2  Program Data

Program Options (h02ccfe.opt)

Program Data (h02ccfe.d)

### 9.3  Program Results

Program Results (h02ccfe.r)