# NAG FL Interfaceh02cff (iqp_​sparse_​optfile)

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## 1Purpose

h02cff may be used to supply optional parameters to h02cef from an external file.

## 2Specification

Fortran Interface
 Subroutine h02cff (
 Integer, Intent (In) :: ioptns Integer, Intent (Out) :: inform
#include <nag.h>
 void h02cff_ (const Integer *ioptns, Integer *inform)
The routine may be called by the names h02cff or nagf_mip_iqp_sparse_optfile.

## 3Description

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 arguments 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 = 1
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 = 1
End
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 12 in h02cef.

None.

## 5Arguments

1: $\mathbf{ioptns}$Integer Input
On entry: the unit number of the options file to be read.
Constraint: $0\le {\mathbf{ioptns}}\le 2147483647$.
2: $\mathbf{inform}$Integer Output
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 $\left[0,2147483647\right]$.
${\mathbf{inform}}=2$
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.

## 6Error 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).

Not applicable.

## 8Parallelism and Performance

h02cff is not thread safe and should not be called from a multithreaded user program. Please see Section 1 in FL Interface Multithreading for more information on thread safety.
h02cff is not threaded in any implementation.

h02cgf 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.

## 10Example

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 10.2). It would usually be more convenient in practice to keep the data file and the options file separate.

### 10.1Program Text

Program Text (h02cffe.f90)

### 10.2Program Data

Program Options (h02cffe.opt)
Program Data (h02cffe.d)

### 10.3Program Results

Program Results (h02cffe.r)