{"id":213,"date":"2012-09-17T02:24:58","date_gmt":"2012-09-17T02:24:58","guid":{"rendered":"http:\/\/solverstudio.org\/?page_id=213"},"modified":"2019-10-15T22:09:21","modified_gmt":"2019-10-15T22:09:21","slug":"pulp","status":"publish","type":"page","link":"https:\/\/solverstudio.org\/languages\/pulp\/","title":{"rendered":"SolverStudio & PuLP"},"content":{"rendered":"

PuLP in SolverStudio
\n<\/strong>PuLP is a modelling environment for building linear and integer programmes within Python.To learn PuLP, read the documentation<\/a>, visit this tutorial<\/a> or watch the Datacamp PuLP Video series<\/a>.<\/p>\n

SolverStudio can run PuLP both using the built-in IronPython (via the SolverStudio language “PuLP (IronPython)” — this is the recommended choice) or using your own external (i.e. manually installed outside SolverStudio) Python installation (via the SolverStudio language “Python (external)”. (Read more about external Python in SolverStudio<\/a>.)<\/p>\n

PuLP comes by default with SolverStudio – you do not need to install it.<\/p>\n

Using PuLP with IronPython<\/strong>
\nPlease see the example below, and the “PuLP Examples.xlsx” example spreadsheet, for samples that illustrate using PuLP. Please also see this SolverStudio IronPython page<\/a> for more details of IronPython’s ability to access the spreadsheet using the standard Excel objects Application<\/a><\/em>, ActiveSheet<\/a><\/em> and ActiveWorkbook<\/a><\/em>.<\/p>\n

Using PuLP with External Python
\n<\/strong>If you run PuLP using Python (External), you need to start your file with:
\nfrom SolverStudio import *<\/em>
\nwhich (1) gives you read and write access to the SovlerStudio Data Items on the sheet, (2) gives you access to the standard Excel objects\u00a0 Application<\/a><\/em>, ActiveSheet<\/a><\/em> and ActiveWorkbook<\/a><\/em>, and (3) adds SolverStudio’s PuLP files the external Python’s path, allowing you to then say:
\nfrom pulp import *<\/em>
\nin the normal way. PuLP works with Python 2.7 and 3.x. Don’t forget that you need to install Python, but not PuLP. (When using SolverStudio, your external Python installation will use the PuLP included in SolverStudio.)<\/p>\n

PuLP Solvers under both IronPython and Python (external)
\n<\/strong>PuLP supports a range of solvers<\/a>. Of these, you can use the “_CMD” solvers under both the “PuLP (IronPython)” and “Python (external) languages, including CBC (i.e. COIN_CMD()), Gurobi (GUROBI_CMD()) and Cplex (CPLEX_CMD()). The other solvers, such as GUROBI(), are only available under “Python(external).”<\/p>\n

The default PuLP solver is CBC, which is included with SolverStudio. You can solve using CBC with any of the following commands:<\/p>\n

prob.solve() # Solve using PuLP's default Solver (usually CBC)\nprob.solve(COIN_CMD()) # Solve using CBC\nprob.solve(COIN_CMD(msg=1)) # Solve using CBC with logging\nprob.solve(COIN()) # COIN is an alias for COIN_CMD\n<\/pre>\n
Other options for CBC include COIN_CMD<\/code>(<\/span>path=None<\/em>, keepFiles=0<\/em>, mip=1<\/em>, msg=0<\/em>, cuts=None<\/em>, presolve=None<\/em>, dual=None<\/em>, strong=None<\/em>, options=[]<\/em>, fracGap=None<\/em>, maxSeconds=None<\/em>, threads=None<\/em>)<\/span><\/p>\n
If you have installed the Gurobi<\/a> or Cplex<\/a> solver, PuLP can use it (under the “PuLP (IronPython)” language) using one of<\/p>\n
prob.solve(GUROBI_CMD()) # Solve using Gurobi\nprob.solve(COIN_CMD(msg=1)) # Solve using CBC with logging\nprob.solve(CPLEX_CMD()) # Solve using Cplex\n<\/pre>\n
The “PuLP Examples.xlsx” workbook (included in the SolverStudio download) has code on the “IronPython Solvers” sheet to list the available solvers.<\/p>\n
PuLP Solvers under Python (External)<\/strong>
\nIf you run PuLP using the “Python (External)” language (i.e. CPython), you can use any of the installed solvers. The “PuLP Examples.xlsx” workbook (included in the SolverStudio download) has code on the “Python (external) Solvers” sheet to list the available solvers.<\/p>\n
SolverStudio with Cut\/Column Generation using DIPPY under Python (External)<\/strong>
\nSolverStudio can work with Dippy<\/a>, the ‘big brother’ of PuLP that allows column and cut generation. Be sure to run under the Python (External)<\/em> language.<\/p>\n
Advanced SolverStudio Usage
\n<\/strong>SolverStudio can work with Dippy<\/a>, the ‘big brother’ of PuLP that allows column and cut generation. Dippy is a joint collaboration between Ted Ralphs and Michael O’Sullivan. Ted has some excellent SolverStudio examples using Dippy on his COIN-Fest 2015 page<\/a>. Be sure to run under the Python (External)<\/em> language.<\/p>\n
COIN Fest 2015: Workshop on Modeling and the COIN-OR Optimization Suite<\/a><\/p><\/blockquote>\n