naginterfaces.library.opt.lp_option_file(ioptns, comm, io_manager=None)[source]

lp_option_file may be used to supply options to lp_solve() from an external file.

For full information please refer to the NAG Library document for e04mg


The unit number (see unit_from_fileobj()) of the options file to be read.

commdict, communication object, modified in place

Communication structure.

This argument must have been initialized by a prior call to nlp1_init().

io_managerFileObjManager, optional

Manager for I/O in this routine.

(errno )

is not in the range .

(errno )

On entry, .

Constraint: .

(errno )

Begin was found, but end-of-file was found before End was found.

(errno )

End-of-file was found before Begin was found.

(errno )

One or more lines of the options file is invalid.


No equivalent traditional C interface for this routine exists in the NAG Library.

lp_option_file may be used to supply values for options to lp_solve(). lp_option_file reads an external file and each line of the file defines a single option. It is only necessary to supply values for those arguments whose values are to be different from their default values.

Each option 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 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 option. 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 int or float value. Such numbers may be up to 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

Printing of user-supplied options is turned off by default, but may be turned on at any time using the keyword ‘List’.

Option settings are preserved following a call to lp_solve() and so the keyword ‘Defaults’ is provided to allow you to reset all the options to their default values before a subsequent call to lp_solve().

A complete list of options, their abbreviations, synonyms and default values is given in Other Parameters for lp_solve.