topic Re: Linear programming (PuLP) for location allocation in ArcGIS Network Analyst Questions

Linear programming (PuLP) for location allocation

LanoYado — Wed, 30 Nov 2016 03:56:30 GMT

I am using the solver "Minimize Facilities" in the location allocation toolbox, but there is a constraint in my problem the solver doesn't allow me to add it. The constraint is for some nodes, the total demand connected to that specific node is n-1, where n is the total number of nodes or lines connected to that node from the neighbor. This is an extra constraint but I couldn't find any way to include it in my problem.

I found a python package called PuLP used for linear programming optimization. Has anyone used it before? Any other toolboxes that can be used for this problem with an option to add mathematic constraints?

Thanks in advance

Re: Linear programming (PuLP) for location allocation

JaySandhu — Sat, 10 Dec 2016 20:03:14 GMT

You can use Network Analyse with external LP solvers using PuLP. An example to do an allocation by first computing the travel cost matrix in ArcMap is here:

http://www.arcgis.com/home/item.html?id=c5ae481f25604d1bb050d9bd1d6e3c06

Jay Sandhu

Re: Linear programming (PuLP) for location allocation

MathewSchmidtlein — Tue, 07 Nov 2017 19:02:59 GMT

Deelesh Mandloi, jsandhu-esristaff

I have used that linked resource (Allocation Tools for ArcGIS) previously (with ArcMap 10.1). I'm trying to use it again(with 10.5), but keep getting an error: [Errno 13] Permission denied: '7476-pulp.mps'. The error is thrown at the point where the LP model is solved (line 479, prob.solve()). There was a similar issue posted in the comments on the page you link a year ago with no response. Do you have any suggestions on how to address this issue? Thanks.

Re: Linear programming (PuLP) for location allocation

RachelApplebaum — Thu, 09 Nov 2017 23:51:42 GMT

Hi Mathew,

I was encountering the same issue so I emailed Deelesh. He has found that this error typically comes from using background processing to run the tool. In my own tests, I found that even if you are using foreground processing, if you have the 64bit background processing extension for ArcMap installed, it will still fail. I was able to get the tool to work by uninstalling the 64bit background processing and running the tool in the foreground.

I think that the issue is caused by the old version of pulp installed with the tool. Newer versiond of the module do support both 32 and 64bit processing, so if you update the pulp module that comes with the tool, the issue with the background processing should go away (though I have not tried that yet.).

Hope this helps!

-Rachel

Re: Linear programming (PuLP) for location allocation

MathewSchmidtlein — Sat, 11 Nov 2017 00:23:27 GMT

Thanks, Rachel. I had been running this in the foreground, but I do believe I have the 64bit background processing installed. But it ran without a hitch once I installed the updated version of PuLP.

Thanks for your help!

Re: Linear programming (PuLP) for location allocation

nataliemartinkus1 — Wed, 17 Jan 2018 22:01:24 GMT

Hi Rachel,

Thanks for the helpful information. I have been trying to install PULP to run with ArcGIS 10.3 and for the life of me cannot figure out how to get it installed. I have tried installing PIP which appears to be needed to install PULP, and can't even get PIP installed. I am no developer, and it seems all the install instructions are written for developers. My goal is to run optimization routines in Python that may or may not involve the use of Network Analyst. Can you help me out since it sounds like you are past the point of installing the program?

thanks,

natalie

Re: Linear programming (PuLP) for location allocation

DeeleshMandloi — Thu, 18 Jan 2018 00:46:44 GMT

Hi Natalie,

If you are looking to install the latest version of pulp on your machine running ArcMap 10.3, you can do the following

1. Download the get-pip.py file from https://bootstrap.pypa.io/get-pip.py and save it locally such as in c:\data folder. The details are at Installation — pip 9.0.1 documentation

2. Open a windows command prompt and type the following command

C:\Python27\ArcGIS10.3\python.exe c:\data\get-pip.py

3. Once pip is installed, install pulp using the following command

C:\Python27\ArcGIS10.3\Scripts\pip.exe install pulp

4. You should now be able to use pulp and arcpy in your python scripts. For example, you can run these commands after starting a python interactive session such as in IDLE

import arcpy
import pulp
print arcpy.GetInstallInfo()
pulp.pulpTestAll()

Hope this helps

Deelesh

Re: Linear programming (PuLP) for location allocation

nataliemartinkus1 — Sat, 27 Jan 2018 00:59:54 GMT

dmandloi-esristaff,

Thank you so much for your succinct directions. I was able to quickly get everything installed, as compared to the hours I spent before going between the PULP and PIP sites. When I run the test you recommend, I get this error shown below in two screen shots, the bottom one showing the final message. Can you please provide any insights on this error?

Thanks,

natalie

Re: Linear programming (PuLP) for location allocation

DeeleshMandloi — Sun, 28 Jan 2018 05:36:57 GMT

Hi Natalie,

The RuntimeError you are encountering is because arcpy is not licensed for use on your machine. This happens when you don't have a license for ArcMap on your machine. If you don't need to use arcpy or cannot install a license for ArcGIS, you can test your pulp installation by running

import pulp
pulp.pulpTestAll()

Thanks

Deelesh

Re: Linear programming (PuLP) for location allocation

nataliemartinkus1 — Mon, 29 Jan 2018 21:16:24 GMT

Hi dmandloi-esristaff,

You are right - I have to connect to a GIS license through the Cisco AnyConnect program since the GIS licenses exist on a university server. I did find that the arcpy module runs when I am connected to the license. Thank you for that info.

However, when I run the PULP test, I get the error below. I sure hope you will have a quick answer to this problem as well.

thanks,

natalie

Re: Linear programming (PuLP) for location allocation

DeeleshMandloi — Mon, 29 Jan 2018 21:57:01 GMT

Hi Natalie,

When I run the tests for pulp 1.6.8 on my windows machine that has 64 bit python 2.7.14, I don't get any such failures. So I am not sure what would be causing this error on your end. Can you try running the pulp tests from the windows command prompt instead of using an IDE like PyScripter?

Python 2.7.14 (v2.7.14:84471935ed, Sep 16 2017, 20:25:58) [MSC v.1500 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import pulp
>>> pulp.pulpTestAll()
Testing zero subtraction
Testing inconsistant lp solution
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 solution with floats in objective
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

Re: Linear programming (PuLP) for location allocation

nataliemartinkus1 — Mon, 29 Jan 2018 22:05:12 GMT

When I ran it as you suggested, I get the same results as you. Does that mean it is installed and ready to go? Im guessing the reason the PyScripter one failed is that the solvers are unavailable, as we saw in the Python run. It fails in the Solver section of the code.

Re: Linear programming (PuLP) for location allocation

DeeleshMandloi — Thu, 01 Feb 2018 16:28:12 GMT

Yes if pulpTestAll is working fine you should be good. You can also try to run some of the examples such as AmericanSteelProblem.py and see if things are working fine.

$ python AmericanSteelProblem.py
('Status:', 'Optimal')
("Route_('Chicago',_'Gary')", '=', 4000.0)
("Route_('Chicago',_'Tempe')", '=', 2000.0)
("Route_('Cincinatti',_'Albany')", '=', 2000.0)
("Route_('Cincinatti',_'Houston')", '=', 3000.0)
("Route_('Kansas_City',_'Houston')", '=', 4000.0)
("Route_('Kansas_City',_'Tempe')", '=', 2000.0)
("Route_('Pittsburgh',_'Chicago')", '=', 3000.0)
("Route_('Pittsburgh',_'Cincinatti')", '=', 2000.0)
("Route_('Pittsburgh',_'Gary')", '=', 2000.0)
("Route_('Pittsburgh',_'Kansas_City')", '=', 3000.0)
("Route_('Youngstown',_'Albany')", '=', 1000.0)
("Route_('Youngstown',_'Chicago')", '=', 3000.0)
("Route_('Youngstown',_'Cincinatti')", '=', 3000.0)
("Route_('Youngstown',_'Kansas_City')", '=', 3000.0)
('Total Cost of Transportation = ', 15005.0)

Re: Linear programming (PuLP) for location allocation

nataliemartinkus1 — Wed, 02 May 2018 23:38:24 GMT

Hi Deelesh,

Thank you again for helping me to get PuLP installed. I copied the American Steel problem into PyScripter, and when I run it I get the following error:

Traceback (most recent call last):
File "<module2>", line 101, in <module>
File "C:\Python27\ArcGIS10.3\lib\site-packages\pulp\pulp.py", line 1513, in writeLP
f = open(filename, "w")
IOError: [Errno 13] Permission denied: 'AmericanSteel.lp'

Is there something simple I need to do to fix this?

Natalie

Re: Linear programming (PuLP) for location allocation

DeeleshMandloi — Thu, 03 May 2018 17:00:09 GMT

Hi Natalie,

Do you get the same error if you run the script from outside of PyScripter such as from the command line?

Thanks

Deelesh

Re: Linear programming (PuLP) for location allocation

nataliemartinkus1 — Thu, 03 May 2018 17:53:10 GMT

I just ran it in Python 2.7 and it worked fine. Thanks for pointing that out.

Natalie

Re: Linear programming (PuLP) for location allocation

DeeleshMandloi — Fri, 04 May 2018 20:24:12 GMT

I don't use PyScripter as my Python IDE. So I am not sure what could be causing the issue. One thing you might want to check is if you are using the correct Python interpreter from within Pyscripter. i.e. PyScripter might be somehow loading the 64 bit version of Python (in case you have both 32 bit and 64 bit versions of Python interpreters installed on your machine).

Re: Linear programming (PuLP) for location allocation

nataliemartinkus1 — Fri, 04 May 2018 20:28:25 GMT

Hi Deelesh,

I was able to solve the problem. It had to do with where I was saving the python script. Thanks for all your help and being so responsive. I greatly appreciate it.