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https://coin-or.github.io/pulp/

A python Linear Programming API
https://coin-or.github.io/pulp/

constraints mip pulp python solver

Last synced: 7 months ago
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A python Linear Programming API

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README 

          
pulp

**************************



.. image:: https://travis-ci.org/coin-or/pulp.svg?branch=master

    :target: https://travis-ci.org/coin-or/pulp

.. image:: https://img.shields.io/pypi/v/pulp

    :target: https://pypi.org/project/PuLP/

    :alt: PyPI

.. image:: https://img.shields.io/pypi/dm/pulp

    :target: https://pypi.org/project/PuLP/

    :alt: PyPI - Downloads



PuLP is an linear and mixed integer programming modeler written in Python. With PuLP, it is simple to create MILP optimisation problems and solve them with the latest open-source (or proprietary) solvers.  PuLP can generate MPS or LP files and call solvers such as GLPK_, COIN-OR CLP/`CBC`_, CPLEX_, GUROBI_, MOSEK_, XPRESS_, CHOCO_, MIPCL_, HiGHS_, SCIP_/FSCIP_.



The documentation for PuLP can be `found here `_.



PuLP is part of the `COIN-OR project `_. 



Installation

================



PuLP requires Python 3.7 or newer.



The easiest way to install PuLP is with ``pip``. If ``pip`` is available on your system, type::



     python -m pip install pulp



Otherwise follow the download instructions on the `PyPi page `_.



Quickstart 

===============



Use ``LpVariable`` to create new variables. To create a variable x with 0  ≤  x  ≤  3::



     from pulp import *

     x = LpVariable("x", 0, 3)



To create a binary variable, y, with values either 0 or 1::



     y = LpVariable("y", cat="Binary")



Use ``LpProblem`` to create new problems. Create a problem called "myProblem" like so::



     prob = LpProblem("myProblem", LpMinimize)



Combine variables in order to create expressions and constraints, and then add them to the problem.::



     prob += x + y <= 2



An expression is a constraint without a right-hand side (RHS) sense (one of ``=``, ``<=`` or ``>=``). If you add an expression to a problem, it will become the objective::



     prob += -4*x + y



To solve the problem  with the default included solver::



     status = prob.solve()



If you want to try another solver to solve the problem::



     status = prob.solve(GLPK(msg = 0))



Display the status of the solution::



     LpStatus[status]

     > 'Optimal'



You can get the value of the variables using ``value``. ex::



     value(x)

     > 2.0



Essential Classes

------------------



* ``LpProblem`` -- Container class for a Linear or Integer programming problem

* ``LpVariable`` -- Variables that are added into constraints in the LP problem

* ``LpConstraint`` -- Constraints of the general form



      a1x1 + a2x2 + ... + anxn (<=, =, >=) b



* ``LpConstraintVar`` -- A special type of constraint for constructing column of the model in column-wise modelling



Useful Functions

------------------



* ``value()`` -- Finds the value of a variable or expression

* ``lpSum()`` -- Given a list of the form [a1*x1, a2*x2, ..., an*xn] will construct a linear expression to be used as a constraint or variable

* ``lpDot()`` -- Given two lists of the form [a1, a2, ..., an] and [x1, x2, ..., xn] will construct a linear expression to be used as a constraint or variable



More Examples

================



Several tutorial are given in `documentation `_ and pure code examples are available in `examples/ directory `_ .



The examples use the default solver (CBC). To use other solvers they must be available (installed and accessible). For more information on how to do that, see the `guide on configuring solvers `_.



For Developers 

================



If you want to install the latest version from GitHub you can run::



    python -m pip install -U git+https://github.com/coin-or/pulp



On Linux and MacOS systems, you must run the tests to make the default solver executable::



     sudo pulptest



Building the documentation

--------------------------



The PuLP documentation is built with `Sphinx `_.  We recommended using a

`virtual environment `_ to build the documentation locally.



To build, run the following in a terminal window, in the PuLP root directory



::



    cd pulp

    python -m pip install -r requirements-dev.txt

    cd doc

    make html



A folder named html will be created inside the ``build/`` directory.

The home page for the documentation is ``doc/build/html/index.html`` which can be opened in a browser.



Contributing to PuLP

-----------------------

Instructions for making your first contribution to PuLP are given `here `_.



**Comments, bug reports, patches and suggestions are very welcome!**



* Comments and suggestions: https://github.com/coin-or/pulp/discussions

* Bug reports: https://github.com/coin-or/pulp/issues

* Patches: https://github.com/coin-or/pulp/pulls



Copyright and License 

=======================

PuLP is distributed under an MIT license. 



     Copyright J.S. Roy, 2003-2005

     Copyright Stuart A. Mitchell

     See the LICENSE file for copyright information.



.. _Python: http://www.python.org/



.. _GLPK: http://www.gnu.org/software/glpk/glpk.html

.. _CBC: https://github.com/coin-or/Cbc

.. _CPLEX: http://www.cplex.com/

.. _GUROBI: http://www.gurobi.com/

.. _MOSEK: https://www.mosek.com/

.. _XPRESS: https://www.fico.com/es/products/fico-xpress-solver

.. _CHOCO: https://choco-solver.org/

.. _MIPCL: http://mipcl-cpp.appspot.com/

.. _SCIP: https://www.scipopt.org/

.. _HiGHS: https://highs.dev

.. _FSCIP: https://ug.zib.de