I’m very pleased to see that the pioneers who played such a pivotal role in creating COIN-OR and all the great software that makes OpenSolver & SolverStudio possible have been awarded the INFORMS 2014 Impact Prize. Well done to Brenda Dietrich, JP Fasano, John Forrest, Lou Hafer, Brady Hunsaker, Laszlo Ladanyi, Robin Lougee, Ted Ralphs, and Matthew Saltzman for all their hard work over the years. They will receive their award at the INFORMS conference Award Ceremony this Sunday.
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Open Source Optimization Workshop 10 Jan, Richmond, VA
Associate Professor Ted Ralphs is organising a COIN-OR workshop:
https://sites.google.com/site/2015icsconference/home/coin-fest
at the Informs Computing Society (ICS) conference in January:
https://www.informs.org/Blogs/E-News-Blog/ICS-2015-Conference
Ted will be demo’ing both OpenSolver and SolverStudio at this event, and also giving an overview of all the other tools COIN-OR makes available.
100k downloads
Great IBM Optimisation Video
Trying to sell optimisation to your colleagues? This IBM video does a good job:
https://www.youtube.com/watch?v=XrMNie-Nzk0&feature=youtu.be
Thanks to Michael Watson for linking to this from his blog.
OpenSolver 2.5.2 alpha (27 Jun 2014)
This is a bugfix release that prevents 32-bit Excel 2013 crashing if the NOMAD non-linear solver is used. Thanks to mbanco for the bug report!
You can get it here. As always we welcome all feedback, especially on our new features.
OpenSolver integration with NEOS servers
The recent alpha releases have featured solvers that interface with the cloud-based NEOS servers to solve the model. NEOS is a free service for solving optimisation problems and can run a large range of solvers. By interacting with NEOS, we gain access to these solvers from anywhere without needing to install them on the computer running OpenSolver.
In order to interact with NEOS, we create an AMPL file that describes the entire model and send this to NEOS for solving. Once NEOS solves the model, it sends back the optimal values, and these are loaded into Excel by OpenSolver.
OpenSolver already fully supports linear programs, and so when a linear solver on NEOS is requested, we can use the existing OpenSolver linear model algorithm to create the AMPL file we need. This algorithm exploits the fact that the model has linear equations, and determines the coefficients by the equations by modifying each decision variable in turn and observing the resulting change (a process that requires many spreadsheet recalculations, and so can be slow). This approach does not work for non-linear models.
Instead, what we do for non-linear models is parse the formulae on the spreadsheet to construct an AMPL model that contains all of the non-linear constraints and/or objectives that we need. We need to convert all of the non-linear Excel formulae into forms that AMPL can understand, allowing us to send the problem to NEOS.
To handle a variety of non-linear models in this way, we need to be able to convert individual Excel functions into valid AMPL code. This is currently handled for some common functions, but others like IF(), MIN() and MAX() have not been implemented yet.
Please try out the NEOS integration for both linear (CBC) and non-linear (Couenne and Bonmin) solvers and let us know how it goes. We welcome any feedback, especially about errors, that will help us improve the translation of complex OpenSolver models into AMPL files.
SolverStudio Speedup: 2 hours to 20 seconds
One of our OpenSolver users recently worked with modelling guru Stu Mitchell to move his model from OpenSolver to SolverStudio. The OpenSolver model originally took 4 hours to solve. After simplifying the spreadsheet, this reduced to 2 hours. Stu created a SolverStudio version that solved the same problem in just 20 seconds. To quote our user: The conversion to SolverStudio has been an excellent improvement.
If you have a complicated spreadsheet, then you may also find that SolverStudio gives much better solve times. Furthermore, the latest SolverStudio release includes ready-to-run models for many common problem formulations, which helps make the conversion even easier. Give it a go, and let us know how you get on.
Andrew
Seeking impact testimonials
OpenSolver would not be possible without the CBC solver developed by the COIN-OR group. Working with colleagues Bob Fourer, Kevin Furman, William Hart and Michael Trick, we are preparing to nominate the initiators and founders of COIN-OR for the 2014 INFORMS Impact Prize. Thus we are soliciting testimonials to the impact that COIN-OR projects, and OpenSolver in particular, have had on diverse research and business activities.
We invite you to send us a paragraph or two describing how OpenSolver software has made a significant difference to your work and accomplishments. Please send your description by June 25 to me at email hidden; JavaScript is required Also feel free to send me any questions about what’s needed.
80,000 downloads
OpenSolver Application for Whirlpool
This is a nice OpenSolver application that gave savings of $1.1M annually:
https://smartech.gatech.edu/handle/1853/42172
Title: | Batching Outbound Shipments for Whirlpool Corporation |
Author: | Bertolino, Michele ; Herbst, Ana ; Jones, Andy ; Liem, Adam ; Nemes, Travis ; O’Gorman, Melanie ; Russell, Samantha ; Sood, Eric |
Abstract: | The team investigated the implementation of batch-picking shipments at a regional distribution center for Whirlpool Corporation, the world’s largest appliance manufacturer. An Excel-based optimization tool was created to strategically batch shipments to more effectively utilize carrying capacity of clamping forklifts across the network. Due to the decrease in labor hours, this resulted in savings of $1.1M annually. |
Informs Transactions on Education: Paul Jenson + SolverStudio
Informs Transactions on Education has just published a special issue in honour of Paul Jenson who developed some excellent Excel tools for teaching operations research and management science. This special issue includes an article on SolverStudio. Cheers, Andrew
Hard IP Guide
This guide, Practical Guidelines for Solving Difficult Mixed Integer Programs, might be useful for people looking for tips on how to solve difficult integer programming models.
INFORMS SolverStudio Presentation
I’ll be presenting on SolverStudio at the INFORMS conference in Minneapolis. Please come along to the Modeling Systems II session “MD08”, Monday Oct 07, 16:30 – 18:00, Level 2 – Room 200H to learn about SolverStudio, or to ask me OpenSolver questions! I look forward to seeing you there. Andrew
Americas Cup Yacht Racing
As a New Zealander and a yachtie, I have been watching the Americas cup racing with great interest as Emirates Team New Zealand races against Oracle Team USA. If you want to see incredible technology and dramatic sailing, check out http://americascup.com – Oracle have done a fantastic job at bringing this racing onto our TVs and browsers. And, Kiwis, don’t forget to wear your red socks… Andrew.
PS: You might also like to read: Philpott, A.B., Mason, A.J., ‘Optimising Yacht Routes under Uncertainty,’ Proceedings of the 15th Chesapeake Sailing Yacht Symposium, Annapolis, Maryland, p89-98, January 2001 (also available here).
50,000 downloads
This says it all: