Installing PuLP at Home

PuLP is a free open source software written in Python. It is used to describe optimisation problems as mathematical models. PuLP can then call any of numerous external LP solvers (CBC, GLPK, CPLEX, Gurobi etc) to solve this model and then use python commands to manipulate and display the solution.

Installation

Note that to install PuLP you must first have a working python installation as described in installing python.

PuLP requires Python >= 2.6.

The latest version of PuLP can be freely obtained from github. Please note that this version of PuLP has not been tested with operating systems other than Microsoft Windows and Ubuntu Linux.

Pip and pypi installation

By far the easiest way to install pulp is through the use of pip and CheeseShop.

  • Install pip
    • In windows (please make sure pip is on your path):

      c:\Python26\Scripts\> pip install pulp
      
    • In Linux:

      $ sudo pip install pulp
      $ sudo pulptest             #needed to get the default solver to work
      
  • Then follow the instructions below to test your installation

To access the examples and pulp source code use the instructions below to install from source

Windows installation from source

  • Install python (installing python)

  • Download the PuLP zipfile

  • Extract the zipfile to a suitable location (such as the desktop - the folder will be no longer required after installation)
    • Open a command prompt by clicking “Run” in the Start Menu, and type ‘cmd’ in the window and push enter.
    • Navigate to the extracted folder with the setup file in it. [Do this by typing ‘cd foldername’ at the prompt, where ‘cd’ stands for current directory and the ‘foldername’ is the name of the folder to open in the path already listed to the left of the prompt. To return back to a root drive, type ‘cd C:’]
    • Type ‘setup.py install’ at the command prompt. This will install all the PuLP functions into Python’s site-packages directory.

The PuLP function library is now able to be imported from any python command line. Go to IDLE or PyDev and type

>>> from pulp import *

to load in the functions. (You need to re-import the functions each time after you close the GUI) PuLP is written in a programming language called Python, and to use PuLP you must write Python code to describe your optimization problem.

Linux Installation

  • Extract the PuLP zipfile folder to a suitable location (such as your home directory - the folder will be no longer required after installation)
  • Open a command line navigate to the extracted zipfile with the setup file in it. [Do this by typing ‘cd foldername’ at the prompt]
  • Type the following at the command prompt. This will install all the PuLP functions into Python’s callable modules.
$ sudo python setup.py install
  • install a solver for pulp to use either
    • use the included 64 or 32-bit binaries cbc-32 and cbc-64
    • install glpk debain based distributions may use the following
    $ sudo apt-get install glpk
    
    • install gurobi (free academic licenses)
    • install cplex (also a license for academics)

Testing your PuLP installation

To test that that you pulp installation is working correctly please type the following into a python interpreter and note that the output should be similar. The output below is what you would expect if you have not installed any other solvers and the CBC solver bundled with pulp works.

>>> import pulp
>>> pulp.pulpTestAll()
         Testing zero subtraction
         Testing continuous LP solution
         Testing maximize continuous LP solution
         Testing unbounded continuous LP solution
         Testing Long Names
         Testing repeated Names
         Testing zero constraint
         Testing zero objective
         Testing LpVariable (not LpAffineExpression) objective
         Testing Long lines in LP
         Testing LpAffineExpression divide
         Testing MIP solution
         Testing MIP relaxation
         Testing feasibility problem (no objective)
         Testing an infeasible problem
         Testing an integer infeasible problem
         Testing column based modelling
         Testing dual variables and slacks reporting
         Testing fractional constraints
         Testing elastic constraints (no change)
         Testing elastic constraints (freebound)
         Testing elastic constraints (penalty unchanged)
         Testing elastic constraints (penalty unbounded)
* Solver pulp.solvers.PULP_CBC_CMD passed.
Solver pulp.solvers.CPLEX_DLL unavailable
Solver pulp.solvers.CPLEX_CMD unavailable
Solver pulp.solvers.CPLEX_PY unavailable
Solver pulp.solvers.COIN_CMD unavailable
Solver pulp.solvers.COINMP_DLL unavailable
Solver pulp.solvers.GLPK_CMD unavailable
Solver pulp.solvers.XPRESS unavailable
Solver pulp.solvers.GUROBI unavailable
Solver pulp.solvers.GUROBI_CMD unavailable
Solver pulp.solvers.PYGLPK unavailable
Solver pulp.solvers.YAPOSIB unavailable