lpp-py

Linear problem parser and dual converter in Python.

YOU NEED numpy FOR THE PROGRAM TO WORK. INSTALL IT WITH pip install numpy

Usage

python3 lpp.py -i <inputFile> [options]

Example usage:

python3 lpp.py -i LP01.LTX

Options

    -i, --input  <inputFile>  : define input file name (mutually exclusive with -l)
    -l, --load   <inputFile>  : define input JSON file name to load
    -j, --json                : export problem in JSON format
    -o, --output <outputFile> : define output file name
                                (Default: '(LP-2)<inputFile>')
    -p, --print               : print the human readable output in the console
    -s, --simple              : export the simple human readable format
    -d, --dual                : convert the problem from primal to dual form

For help, use:

python3 lpp.py -h

or

python3 lpp.py --help

About input files:

You can either load an already saved json file, created with this program via -l or --load, but should be used instead of -i or --input.

Otherwise, the input file should follow some specific rules. Take a look below about what is true as well.

• Start with the type of problem, min or max.
• Follow up with the objective function, preferably on the same line.
• Variable names must have specific names, like x1, x2, ..., xN. More specifically x and a number exactly after it.
• Capitalization does NOT matter, in anything.
• The order each variable is stated in an expression also does NOT matter.
• After objective function you must use the keyword(s) s.t. or subject to and state each one per line.
• Whitespace is irrelevant.
• Optionally, you can use the keyword with and state the natural constraints per line. To do so, state the variable name, then type free or >=0 or <=0.
• You must ALWAYS type the end keyword when you are done.
• You can potentially write whatever else you like in the file and the parser will do it's utmost best to ignore them and only parse what it cares about. Take a look at the examples folder, there are some examples that cover most cases and answer additional questions you might have.